Mobile Cartography – Adaptive Visualisation of Geographic ... · mobile map services, yet LBS...

Institut für Photogrammetrie und Kartographie

Mobile Cartography – Adaptive Visualisation of Geographic Information on Mobile Devices

Tumasch Reichenbacher

Vollständiger Abdruck

der von der Fakultät für Bauingenieur– und Vermessungswesen

der Technischen Universität München

zur Erlangung des akademischen Grades eines

Doktor der Naturwissenschaften (Dr. rer. nat.)

genehmigten Dissertation.

Vorsitzender: Univ. Prof. Dr.-Ing. habil. Thomas Wunderlich

Prüfer der Dissertation:

1. Univ. Prof. Dr.-Ing. habil. Liqiu Meng

2. Priv.-Doz. Dr. rer. nat. Doris Dransch, Humboldt Universität zu Berlin

3. Univ. Prof. Dr.-Ing. habil. Monika Sester, Universität Hannover

Die Dissertation wurde am 20.11.2003 bei der Technischen Universität München eingereicht und

durch die Fakultät für Bauingenieur– und Vermessungswesen am 22.01.2004 angenommen.

Abstract

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Abstract The progresses in the fields of mobile Internet and positioning methods have lead to a plethora of new possibilities for cartography in mobile usage environments. However, principles of web mapping cannot simply be transferred to the mobile environment. Likewise the availability of Location Based Services (LBS) has made it possible to develop mobile map services, yet LBS themselves are mainly driven by technology and only con-cerned with location-related issues, thus have rather limited meaning for the usability study. This work has introduced a new and comprehensive conceptual framework of mobile cartography, thus established an instrument for the design of useful and usable geovisualisation services. The research enriches and extends cartographic theory and methods in the field of geographic information communication in mobile environments and adaptive methods for cartographic visualisation. It established new concepts for mo-bile cartography and showed the differences, but also the similarities towards traditional cartography and web cartography. The main focus is on the elaboration of adaptive methods for visualisation of geographic information for mobile usage, i.e. on mobile devices. Adaptation takes place in the components such as the mobile user, his/her activities with associated goals, as well as the situation they are placed in. The usage sce-narios described were helpful for the implementation of a rudimentary, prototypical adaptive geovisualisation service for mobile users. The service for the example of point symbol maps was implemented based on open-standard formats and served as a proof of concept. It basically demonstrates how a mobile client can send as Simple Object Access Protocol (SOAP) encoded context parameters to a web service. The service handles the user demand by sending a request for the required geospatial data and maybe additional filters to a Web Feature Server. The result, a Geography Markup Language (GML) document is transformed through an Extensible Stylesheet Language Transformation (XSLT) into a Scalable Vector Graphics (SVG) document. Further adaptations of the SVG document can be effected by manipulating the Document Object Model (DOM). Finally, the web service returns the result as a SVG map back to the client. A few examples generated with this geovisualisa-tion service demonstrate the potential of map adaptation to mobile user activities.

Zusammenfassung

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Zusammenfassung

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Zusammenfassung Entwicklungen im Bereich des mobilen Internets und der Positionierungsmethoden führen zu neuen Möglichkeiten für die Kartographie im mobilen Nutzungsumfeld. Allerdings sind die herkömmlichen Ansätze der Internetkartographie nicht ohne weiteres übertragbar. Ebenso bilden Location Based Services zwar eine gute Grundlage für die Entwicklung von mobilen Kartendiensten, aber die Techniklastigkeit und Ein-schränkung auf die Ortsinformation schränken die Brauchbarkeit ein. Mit der Einführung eines umfassenden neuen Forschungsrahmen für die mobile Kartographie, dessen wesentlicher Punkt der Kontext der Nutzung und die Anpassung der Geovisu-alisierung an diesen Nutzungskontext ist, wird ein Instrument für die Entwicklung von brauchbaren mobilen Geovisualisierungsdiensten geschaffen. Der Forschungsrahmen vereint dabei Geoinformation, Visualisierung, Kontext und Adaption in geeigneter Weise, sodass aufgrund der Kontextinformation die Visualisierung von Geoinformation auf mobilen Geräten adaptiert werden kann. Kontext wird dabei umfassender verstan-den und beinhaltet neben der Ortsinformation die Zeit, den Nutzer, die mobilen Nutzeraktivitäten, die Geoinformation, die technischen Gegebenheiten, sowie die Bezie-hungen zwischen diesen Elementen. Die Modellierung des Kontexts der mobilen Geoinformationsnutzung schafft die Grundlage für die Übertragung des Adaptionskon-zeptes aus dem Bereich der Benutzerschnittstellen und Hypermedien in die Kartographie. Die Analyse der wesentlichen Adaptionsdimensionen der Kartographie ermöglicht die Vorschläge von Methoden zur Adaption der Geoinformation in mobilen Geovisualisierungsdiensten. Als Nachweis der Machbarkeit wird anhand von Punktsymbolkarten ein rudimentärer, prototypischer adaptiver Geovisualisierungsdienst auf Basis von offenen Standards implementiert. Im Wesentlichen wird dabei gezeigt, wie ein mobiler Client als Simple Object Access Protocol (SOAP) kodierte Anfragen an einen Web Service schickt, die die erforderlichen Kontetxtinformationen beinhalten. Der Service behandelt die Nutzeranfrage indem er die Anfrage der entsprechenden Geodaten, eventuell mit zusätzlichen Filtern versehen, an einen Web Feature Server schickt und das Resultat, ein Geography Markup Language (GML) Dokument, weiterbehandelt. Dazu gehört die Transformation mittels Extensible Stylesheet Language Transformation (XSLT) in ein Scalable Vector Graphics (SVG) Dokument sowie weitere Adaptionen des SVG Dokuments über das Document Object Model (DOM). Zuletzt sendet der Web Service das Ergebnis in Form einer SVG Karte an den Client zurück. Einige mittels dieses Geovisualisierungsdienstes er-zeugte Beispiele verdeutlichen insbesondere die Möglichkeiten der Anpassung der Karten an die Aktivitäten des mobilen Nutzers.

Acknowledgements

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Acknowledgements

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Acknowledgements This research was conducted from May 2000 until November 2003 at the Department of Cartography at the Technical University of Munich. Many people went along with me on this path in the one or other way.

First of all, I would like to thank Prof. Dr. Liqiu Meng for her steady interest in my work, her ever open door, her well-considered remarks on my work, her ability to pre-sent me a map through the research jungle, and most of all allowing me vast freedom in my research.

I am grateful of having been accompanied along the path of writing this dissertation by PD Dr. Doris Dransch and of having her as a reviewer. She offered many precious hints on this work, surprised me with her hospitality and her encouragements were motivat-ing in the dark hours of a PhD candidate.

Thanks go in the same extent to Prof. Dr. Monika Sester for her interest in my work and her helpful comments on the sloppy passages of my work and her willingness to act as a reviewer of this dissertation.

I would like to mention Prof. Dr. Alexander Zipf, whose research gave me the idea for this dissertation. Further inspiration, comments and support during the last year of this work came from Prof. Dr. Robert Weibel and his team, Dr. Dirk Burghardt and Alistair Edwardes. The same commitment can be attributed to Birgit Elias, Mark Hampe, and Dr. Tiina Sarjakoski.

I also wish to thank my colleagues at the Department, especially Daniela Toellner for her help implementing the client application.

The test data used in the dissertation was kindly provided by ‘Vermessungsamt der Stadt München’ and ‘Bayerisches Landesvermessungsamt’ (Herr Johann Messerer).

I have also benefited from conversations with my friends Helen Wagner Häberling and Christian Häberling, who encouraged me, shared the ups and downs and are among others a link to the Swiss cartography community. Regula Achermann made subtle im-provements of the layout and Patrick Schärer showed continuous interest in my whereabouts.

My parents, Hanspeter and Elisabeth Reichenbacher, who made it possible for me to achieve my formal and informal education, gave me a critical attitude on my way, and had always trust in me, deserve special gratitude.

In particular I am indebted to my wife Brigitte for her great patience over the last four years, for her support in any dimension, for proof reading, and for being the necessary touch to reality.

List of Figures

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List of Figures

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List of Figures Fig. 1: Thesis structure ......................................................................................................................... 6 Fig. 2: Focus of thesis related to MacEachren’s map cube.............................................................. 8 Fig. 3: Theoretical model and applied theories for adaptive geovisualisation.......................... 10 Fig. 4: Interaction framework (Dix et al. 1998, p. 107) .................................................................. 12 Fig. 5: System acceptability attributes (Nielsen 1993, p. 25) ........................................................ 15 Fig. 6: Elements of activity theory (after Engeström 1987)........................................................... 18 Fig. 7: Levels of activity (Kuutti 1996, p. 30) .................................................................................. 19 Fig. 8: Process model of activity theory (adapted from Werlen 1988, p. 13) ............................. 19 Fig. 9: Basic principle of adaptation systems.................................................................................. 22 Fig. 10: Adaptation spectrum ........................................................................................................... 22 Fig. 11: Agents involved and stages in the adaptation process (Dietrich et al. 1993).............. 25 Fig. 12: Different types of adaptation (Dietrich et al. 1993, p. 17) .............................................. 25 Fig. 13: Relevant technologies for mobile cartography................................................................. 33 Fig. 14: Web service model................................................................................................................ 37 Fig. 15: OpenLS Framework (after OGC 2003) .............................................................................. 40 Fig. 16: LoL@ Prototype and GiMoDig design proposal for navigation map ........................... 47 Fig. 17: Examples of car navigation system map displays and LBS............................................ 50 Fig. 18: Variable-scale map for small displays and radial generalisation in variable-scale

maps ........................................................................................................................................ 51 Fig. 19: Schematic map and topogram ............................................................................................ 52 Fig. 20: Conceptual framework of mobile cartography ................................................................ 62 Fig. 21: Typical spatial questions (adapted from Kraak and Ormeling 1996) .......................... 63 Fig. 22: Spatial scope of activities (adapted from Heidmann and Hermann 2003, p. 126) ..... 67 Fig. 23: Modular construction of activities based on single actions............................................ 70 Fig. 24: Dimensions of the geographic information usage context ............................................. 72 Fig. 25: Generic context model for mobile cartography................................................................ 73 Fig. 26: Spatial and temporal relevance function (adapted from Schmidt and Gellersen 2001)

.................................................................................................................................................. 80 Fig. 27: Hierarchical levels of context .............................................................................................. 81 Fig. 28: Geographic information modelling ................................................................................... 83 Fig. 29: Relationship of information types...................................................................................... 84 Fig. 30: Question and answer model (adapted from Heidmann 1999, p. 97)............................ 86 Fig. 31: The sense-making triangle................................................................................................... 88 Fig. 32: An example of event relevance........................................................................................... 91 Fig. 33: Visual task taxonomy (after Zhou and Feiner 1998) ....................................................... 96 Fig. 34: Domains of adaptation....................................................................................................... 101 Fig. 35: Dimensions of adaptation in mobile cartography ......................................................... 101 Fig. 36: Adaptation process in mobile cartography..................................................................... 104 Fig. 37: Adaptable objects in the geovisualisation process......................................................... 105 Fig. 38: Plasticity of user interfaces................................................................................................ 109 Fig. 39: Design space, adaptation space and map niche ............................................................. 110 Fig. 40: Internal map adaptation based on constraints ............................................................... 111 Fig. 41: Scenario based design approach (BTexactTechnologies 2003) ................................... 119 Fig. 42: Test area (map from Neudeck 2001)................................................................................ 119 Fig. 43: Methods for emphasizing map objects: opacity and crispness .................................... 125

List of Figures

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Fig. 44: Semi-transparent overlay in mobile maps for orientation or distance information . 126 Fig. 45: Map scale adaptation ......................................................................................................... 127 Fig. 46: Route-focussed maps ......................................................................................................... 129 Fig. 47: Location map....................................................................................................................... 129 Fig. 48: Route maps .......................................................................................................................... 130 Fig. 49: Search result map ............................................................................................................... 130 Fig. 50: Map with further information for identified feature..................................................... 131 Fig. 51: Event and object state map................................................................................................ 131 Fig. 52: Design for mobility: Falk Cityguide and Pocket Streetmap......................................... 132 Fig. 53: Perspective views and 3D landmark symbol.................................................................. 133 Fig. 54: Silhouette view of landmarks (Gartner 2003)................................................................. 133 Fig. 55: Orthophoto with thematic overlay................................................................................... 133 Fig. 56: Implementation platform architecture ............................................................................ 139 Fig. 57: TinyLine viewer applet and mock-up client................................................................... 143 Fig. 58: Coordinate systems of GML and SVG............................................................................. 145 Fig. 59: Sequence diagram of the geovisualisation test service ................................................. 145 Fig. 60: Adapmap architecture.......................................................................................................... 146 Fig. 61: SAX and DOM cooperation (McLaughlin 2001)............................................................ 147

List of Tables

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List of Tables Table 1: Terminology of adaptation dimensions ........................................................................... 23 Table 2: Adaptable and adaptive systems (Fischer 2001) ............................................................. 24 Table 3: ISO Geographic services ..................................................................................................... 39 Table 4: Comparison of map products and geovisualisation services........................................ 42 Table 5: Characteristics of different map groups ........................................................................... 58 Table 6: Relationship between spatial user actions and GIS operations .................................... 68 Table 7: Elementary mobile user actions with spatial relation .................................................... 69 Table 8: Dimensions of context in mobile cartography................................................................. 73 Table 9: Sample event table............................................................................................................... 91 Table 10: Relevance results for event query ................................................................................... 92 Table 11: Adaptable objects of geovisualisation and their value domains .............................. 107 Table 12: Comparison of adaptation and generalisation ............................................................ 116 Table 13: Use cases for the elementary spatial actions................................................................ 138 Table 14: Geospatial data sources .................................................................................................. 141 Table 15: POI table............................................................................................................................ 141

Table of Contents

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Table of Contents

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Table of Contents Abstract iii Zusammenfassung v Acknowledgements vii List of Figures ix List of Tables xi Table of Contents xiii 1 Introduction 1

1.1 Motivation 1 1.2 Thesis objectives 4 1.3 Thesis structure 5

2 Scope 7 2.1 Theoretical background 7

2.1.1 Human computer interaction 10 2.1.2 Activity theory 17 2.1.3 Context 20 2.1.4 Adaptation 21 2.1.5 Inter-relationships of relevant theories and their applications in cartography 29

2.2 Technical background 32 2.2.1 Mobile computing 33 2.2.2 Web Services, Geoservices, and Location Based Services 36

3 Approaches for visualisation of geographic information on mobile devices 43 3.1 Related work 43

3.1.1 Research approaches 44 3.1.2 Existing solutions 49

3.2 Evaluation of approaches and solutions 53 4 A new and comprehensive conceptual framework of mobile cartography 57

4.1 Rationale for a mobile cartography 57 4.2 A framework of mobile cartography 61

4.2.1 Mobile users 63 4.2.2 Mobile activities 66 4.2.3 Mobile context 72 4.2.4 Information in mobile enviroments 82 4.2.5 User interfaces and mobile geovisualisation 92 4.2.6 Visualisation in mobile cartography 92 4.2.7 Technology in mobile cartography 97 4.2.8 Summary 98

5 Adaptive visualisation of geographic information 99 5.1 Transfer of the adaptation concept to geographic information visualisation 99 5.2 Adaptation dimensions in geographic information visualisation 100

5.2.1 Adaptation process 103 5.2.2 Adaptation objects 104 5.2.3 Adaptation target 107 5.2.4 Triggers and control of adaptation processes 108 5.2.5 Adaptation methods 112 5.2.6 Evaluation of adaptation processes 114

Table of Contents

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5.3 Adaptation and generalisation 114 5.4 Adaptive visualisation of geographic information on mobile devices 116

5.4.1 Scenarios for adaptive visualisation of geographic information on mobile devices 116 5.4.2 Adaptive visualisation methods for geographic information on mobile devices 122

6 Service design for integrating adaptation into geovisualisation 135 6.1 Use cases for adaptive geovisualisation services on mobile devices 135 6.2 Implementation of a prototypical adaptive geovisualisation service 138

6.2.1 Platform 139 6.2.2 Testbed 140 6.2.3 Prototype functionality 142

7 Conclusion 149 7.1 Achievements 149 7.2 Insights 150 7.3 Outlook 152

7.3.1 Suggested improvements 152 7.3.2 Concluding remarks 154

Bibliography 155 Appendix: Abbreviations 175

1

Chapter 1

1 Introduction

“But is thought continuous, inescapable, or is it as somebody said against Descartes, sometimes I think and sometimes I just am ...” – David Lodge, ‘Thinks …’

1.1 Motivation

One of the characteristic features of our society is the constantly growing mobility, lately also combined with an increasing desire for mobile usage of computing and communication tools. This trend can be observed in the rapid spread of laptops, mobile phones and other mobile devices. Another trend is the ‘democrati-sation’ of computer usage. For years geographic information sys-tems (GIS) have for example been a tool for experts, running only on expensive machines requiring professional skills. In the early nineties easy-to-use desktop GISs were introduced. With the wide-spread Internet and web mapping a further ‘democratisation’ of geographic information use took place. And now, after the tre-mendous success of the Internet and the cellular telephone over the last decade, the next technological wave seems to be the con-vergence of the two: the mobile Internet (Andersson and Svensson 1999). This brings web GIS and web mapping a step further, since the dissemination of digital geospatial data is no longer bound to the desktop platform. And finally we are on our way to an information society. The availability of current and rele-vant information is of great importance for our daily life (Negroponte 1995). The impact of the Internet is enormous. The technological progresses are partly accompanied by and partly the motor for different social trends. One trend, globalisation, is tightly coupled to an ever faster, mobility-defined life. Mobility leads to the fact that more people travel and move in areas unfamiliar to them. The global village metaphor also holds for the wish to dif-ferentiate oneself from the average mass leading to a growing

(Andersson and Svensson, 1999) Andersson, C. and Svensson, P. (1999): Mobile Internet - An industry-wide para-digm shift?, Ericsson Review(4): 206-213

(Negroponte, 1995) Negroponte, N. (1995): Being digital, London: Hodder & Stoughton

1 Introduction

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trend towards individualisation (or personalisation). A world, however, which becomes increasingly global and spins faster and faster calls for order and security. In such a modern world people do not necessarily have more freedom, but are forced to manage their individual lives and their mobile everyday activities, which gets more and more complicated. The organisation of this acceler-ated daily life requires supporting tools and information. This is especially the case for geographic information that is attached to almost any everyday activity.

The emergence of mobile computing along with wireless devices has brought about a whole palette of new possibilities for car-tography. New mobile devices such as Personal Digital Assistants (PDA), Smartphones and the like, have inherent advantages con-cerning personal assistance in mobile environments: they can present up-to-date geospatial information in an individual, dynamic, and flexible way to mobile users, i.e. unbound to space.

Other important trends in information technology that have in-creasingly gained attention in the field of cartography are user focus, personalisation, and context awareness. The incorporation of these trends could result in more adaptive systems. The chal-lenge for modern cartography lies in supporting as many people as possible with mobile usage of geographic information. A mobile assistance system would incorporate analytical functions, be aware of the user’s context and characteristics to assist the user in a mobile environment. This kind of mobile assistance is the only way to ensure also for future times an efficient communication of geographic information and to prove the usability of new mobile technologies. In order to achieve this, a substantial amount of adaptation is indispensable. There are three reasons for this. First, the increasing quantity of information and the danger of over-stimulation urge a suitable channelling of the information stream. Second, adaptation could lead to greater acceptance of new, yet partially still immature technologies. Third, new value-added (web) services which users have to pay for need customisation to guarantee user satisfaction.

A possible solution to these challenges is an adaptation in the sense of providing the user more relevant, detailed, accurate and thus adequate information meeting his/her needs better. Cartogra-phy should provide new and enhanced services that could be combined with existing services, thus bring added value to users. In this sense, cartography should become a more service-oriented business. These new services ought to close the gap between the

1 Introduction

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benefits of web mapping or online GIS and the freedom of mobility. Today some people use highly sophisticated web-based applications to extract geographic information only to print out the results (e.g. a city map or a route description) for having them at hand when they will move around later on. This deviation and degrading of an information delivering process makes little sense. After all, even if this proceeding is considered a valuable approach, due to its static nature it is not able to support many requirements of human life, such as spontaneous decisions and serendipities.

Furthermore there are three critical elements requiring an instant information access during mobility: time, location, and physical conditions. On the one hand there are many situations where there is no time to look up some information later at a stationary, wired PC or an Internet appliance. The information has to be timely, the access immediate. On the other hand many situations are imagin-able where time is not a critical factor, but we are at a certain place and need some information related to this place. It would be rather inefficient and inconvenient to go away in order to gather the required information and later come back to the same place to actually use the information. Sometimes this approach is even im-possible (e.g. if one is at a place only once in a lifetime). Finally, special physical conditions could require instant information access (e.g. natural hazards such as a storm or fire). Naturally, this factor is tightly coupled with time and location. One needs the information, because one is right here, right now.

Although the technological progress in the field of mobile com-puting is significant and more and more research is directed to mobile usage of geographic information, several problems are yet unsolved and many gaps are to be bridged when it comes to developing solutions for the mobile context:

• Geovisualisation for the small displays of mobile devices is restricted by several technical limitations, such as the small display size and resolution, the lack of processing power and memory, and most critical the battery lifetime. Furthermore, the mobile network bandwidth is consid-erably smaller than that in fixed networks.

• The usability of mobile geovisualisation solutions is hin-dered by inadequate geovisualisation. The causes are either the use of scanned paper maps designed for a medium with different characteristics or the production of illegible and cluttered maps that fit a large screen, but not the small mobile device screen with lower resolution.

1 Introduction

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Geovisualisation that is not adapted to the usage context, supporting functionality that is not tailored to the users’ mobile activities, and poorly designed user interfaces not taking into account the different input modes and condi-tions of mobile interactivity cause further usability prob-lems.

• The geovisualisation on small displays is dominated by the constraint of the small display. This poses an immense generalisation pressure. However, generalisation alone cannot assure the fitness for use required in mobile geo-graphic information usage situations. The lack of map space also implies that there is no room for auxiliary ele-ments such as a map legend, which makes the map read-ing process difficult. Furthermore the overview function of maps is missing.

• The mobility of the user has many consequences: the usage of geographic information is very different from a stationary case and is affected by changing modes of movement, different and changing activities beside the usage, a potential of distractions, different and fast changing contexts, and harder usage conditions, e.g. a limited time budget.

1.2 Thesis objectives The overall objective of this thesis is to establish a conceptual framework for mobile cartography and adaptive visualisation of geographic information on mobile devices by transferring the adaptation approach to the domain of cartography in mobile environments. This research work claims to open and define a new research field in cartography. In addition, the dissertation aims at demonstrating the value of a top-down approach for developing cartographic solutions in a mobile environment.

The focus is on non-explorative, communicative mobile usage of geographic information in urban environments. The main goal is to communicate geographic information in a supportive way rather than learning or exploring. Emphasis is put on the support of everyday activities of mobile users by offering fast and non-intrusive information presentations for quick decisions.

The following list describes the general objectives of this thesis: • Providing a framework for mobile cartography and adap-

tive geovisualisation

1 Introduction

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• Identifying the links and interfaces to related disciplines and methods

The more specific objectives include: • Developing adaptation methods for geovisualisation • Demonstrating the potential of Scalable Vector Graphics

for mobile cartography and adaptive geovisualisation • Implementing a prototype mobile geovisualisation ser-

vice for mobile users serving as a proof of concept for the mobile cartography framework

1.3 Thesis structure The remainder of the thesis is structured as follows (see Fig. 1):

This chapter introduced the problems and challenges of visuali-sations for mobile devices and outlined the goals and contributions of this thesis.

Chapter 2 presents the scope of this research work and develops the theoretical and technical background. First, the theories central to mobile cartography are reviewed independently followed by a contemplation of their relationships to cartography. Second, the basic technologies relevant to mobile cartography are described.

Chapter 3 reviews existing approaches and solutions for geo-graphic information visualisation on mobile devices. An evaluation of these approaches reveals the gaps and deficiencies and confirms the need for a fresh approach.

Chapter 4 introduces a new and comprehensive conceptual framework for mobile cartography. After a discussion of the rationale, the building blocks, user, activity, context, information, user interface, visualisation, and technology are elaborated in fur-ther detail.

Chapter 5 first describes the transfer of the adaptation concept to cartography and the core elements of adaptive visualisation. Thereafter it illustrates methods for geovisualisation adaptation.

Chapter 6 describes the design of a prototype geovisualisation service with adaptation capabilities.

Chapter 7 gives a synopsis of mobile cartography and evaluates the framework, draws the conclusions and identifies further work to be done in this research field.

1 Introduction

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Fig. 1: Thesis structure

7

Chapter 2

2 Scope

“The difference between theory and practice is smaller in theory than in practice.” – Anonymous

2.1 Theoretical background

The grounding theory for this work is information and communi-cation theory with respect to cartography. This theory is involved in questions of modelling, structuring and transforming geo-graphic information for mobile usage purposes. In the last thirty years several models of the cartographic communication process and a system of related models have been proposed by cartogra-phers. This cartographic theory which by itself makes vast use of other theories has been discussed by many authors, e.g. (MacEachren 1995; Buziek 2001; Freitag 2001). These contributions mention different theories involved in cartographic visualisation: information and communication theory, model theory, semiotics, system theory, cognitive theory, and activity theory. In recent years the methods and tools of cartography have been extended by some exponents in the discipline towards communication of geo-graphic information through animated and auditory elements. However, in this work the focus is on cartographic visualisation. Therefore methods of visual design and concepts from semiotics are borrowed. Meng (2003) argues that not only the cartographic methods and consequently the context of mapmaking have changed, but also the contexts of map use. Despite the shift to context in use and new, non-visual means the visual remains vital for cartography. Buttenfield and Mackaness (1991, p. 432) give a comprehensive definition of visualisation:

Visualization is the process of representing information synopti-cally for the purpose of recognizing, communicating and inter-preting patterns and structure. Its domain encompasses the computational, cognitive, and mechanical aspects of generating,

(Meng, 2003) Meng, L. (2003): Missing Theories And Methods In Digital Cartography, Pro-ceedings 21st International Cartographic Conference, Durban, South Africa, August 10-16, 2003

(Buttenfield and Mackaness, 1991) Buttenfield, B. P. and Mackaness, W. (1991): Visualization, in D. J. Maguire, M. F. Goodchild and D. Rhind (Eds.), Geographical Information Systems: Principles and Applications, 1, New York (NY): John Wiley & Sons

(MacEachren, 1995) MacEachren, A. M. (1995): How maps work: representation, visualization, and design, New York (NY): Guilford Press

(Buziek, 2001) Buziek, G. (2001): Eine Konzeption der kartographischen Visualisierung, Habili-tationsschrift, Institut für Kartographie und Geoinformatik, Universität Hannover

(Freitag, 2001) Freitag, U. (2001): Die Entwicklung der Theorie der Kartographie, Karto-graphische Bausteine Band 19

2 Scope

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organizing, manipulating and comprehending such representa-tions. Representations may be rendered symbolically, graphi-cally, or iconically and are most often differentiated from other forms of expression (textual, verbal, or formulaic) by virtue of their synoptic format and with qualities traditionally described by the term ´Gestalt´.

The different kinds of cartographic visualisation are profoundly examined by MacEachren (1995). The two main types of cartogra-phies distinguished are communication oriented and explorative visualisation oriented cartography. For better understanding MacEachren proposed a map cube spawn by the major dimen-sions of map use: target audience, presentation intentionality, and degree of human-map interaction (see Fig. 2). A similar distinction has been proposed by DiBiase (1990). In his schema the presenta-tion of geographic information in the public realm is named visual communication in opposition to visual thinking. The present work concentrates on communicating known geographic information (knowns) to individual users for private use or according to DiBiase the visual communication, however in a more private realm. And the human-computer interaction is compared to desktop environ-ments low for reasons to be discussed.

Fig. 2: Focus of thesis related to MacEachren’s map cube

For the rest of this dissertation the term geovisualisation is usu-ally preferred over the term map, because the expression means of visualisations of geographic information in mobile environments

(DiBiase, 1990) DiBiase, D. (1990): Visualization in the earth sciences, Bulletin of the College of Earth and Mineral Sciences, Pennsylvania State University 59(2): 13-18

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can exceed the traditional meaning of a map. Thus the term map is considered too narrow for representations on mobile devices, although the examples in this thesis are not stretching these limits. Geovisualisation is here understood as any kind of visualisation of geographic information (including perspective views, photo-graphs, panoramas, animations, acoustic elements) without a focus on exploratory data analysis, though.

Since this work aims at extending existing cartographic theory towards adaptation and mobile usage of geographic information, it first has to clarify the theoretical foundation and its interrelation with this dissertation. These theories contribute in different ways to the problem of visualising geographic information in mobile environments. Fig. 3 shows an overview of the different theoretic fragments related to this work.

This chapter covers the most relevant theories for communicating spatial information in mobile environments. For identifying and modelling mobile user tasks and usage issues activity theory is incorporated. Mobile usage per se and adapting visualisation to this mobile usage situation is strongly connected to context theory. Different theories and principles of human computer interaction, e.g. cognitive science theory, interactivity, and usability principles are applied to user focus issues and user task analysis. The basic principles of adaptation prepare the terrain for adapting geo-graphic information in mobile usage situations.

These theories and the ones not yet mentioned here, i.e. informa-tion and communication theory and model theory, are discussed in chapter 4 in the context of their usefulness for mobile geovisu-alisation, where they are combined to build the framework of mobile cartography. The more subsidiary theories like theories about technology adoption and scenario based design are covered in chapter 5.

2 Scope

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mobility

human computer interaction• interactivity• adaptation• usability• cognitive approaches

activity theory• mobile user activities• user goals• operations• social factors

adaptation• adaptability• adaptivity• adaptation methods

context theory• situated action (models)• activity context• physical & social context• context-awareness

Fig. 3: Theoretical model and applied theories for adaptive geovisuali-sation

2.1.1 Human computer interaction

The mobile environment and the mobile usage situation differ in many respects from a stationary one. The mobile environment has its own characteristics. Mobility and most mobile activities limit our possibilities and shape the way we do things. A major factor is the overwhelming stream of external stimuli. We cannot cope with all of them simultaneously. The focus of attention is thus not always on the system in use or the user interface respectively. Opposed to stationary usage with virtual environments in the hyperspace, the mobile user is much more engaged with the real environment. This includes the wishes or needs to perform activi-ties in parallel to system usage and hence a too intrusive system would be disturbing or even threatening a successful activity per-formance. That means that too much direct interaction is not possi-ble in mobile contexts. There generally is no time to manually filter the relevant information needed in a specific usage situation. This fact is precisely described in (Smailagic and Siewiorek 2002):

Distractions pose even more of a problem in mobile environ-ments than in desktop environments because mobile users often must continue walking, driving, or taking part in other real-world interactions. A ubiquitous computing environment that minimizes distraction should therefore include a context-aware system able to ´read´ its user’s state and surroundings and modify its behaviour on the basis of this information. The system can also act as a proactive assistant by linking information such as location and schedule derived from many contexts, making decisions, and anticipating user needs. Mobile computers that

mobile HCI interactivity usability mobile usability problems

(Smailagic and Siewiorek, 2002) Smailagic, A. and Siewiorek, D. (2002): Application Design for Wearable and Context-Aware Computers, pervasive computing(October-December): 20-29

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can exploit contextual information will significantly reduce de-mands on human attention.

This statement makes it clear that interacting with computers in mobile environments is quite different from interacting with sta-tionary computers. Though there certainly always is and needs to be some kind of interaction between the system and the user, the degree of interactivity must be minimised, i.e. interactive functions should be sparingly used and the kind of interactions should be wisely chosen in mobile usage contexts respectively. Interactivity has to be adapted to the mobile usage environment to enable the user to achieve his/her information needs with a maximum of relevance for a minimum of interactive input. To clarify this state-ment interactivity is first defined in general and later re-considered in a mobile context. Interactivity

The term interactive became popular in information technology in the late 1970ies with the introduction of the first graphical user interface at Xerox Palo Alto Research Centre later incorporated in the first Apple Macintosh. There are different notions and defini-tions of the term interactive. A useful definition provides Steuer (1994) stating that interactivity is “the extent to which users can participate in modifying the form and content of a mediated envi-ronment in real time”.

From the literature review (Heeter 1989; Haack 1995) a few constituting elements can be identified:

• active role of user • degrees of freedom in choices of content and functions • selection, appearance, and order of information items

changeable by the user • possibility of customisation through the user

It is important to separate the physical or technical interactions from symbolic interactions, i.e. the surface and deep structure of interaction. Hitting a button or moving the mouse is a surface, physical or explicit interaction, while a symbolic or implicit inter-action is for instance the selection of a menu option.

Interactivity is a more intuitive way of working with a computer. This intuitive approach in HCI has the objective to make the use of a computer easier, faster to learn and more transparent to the user. Dix et al. (1998, p. 104) state that “the purpose of an interactive system is to aid a user in accomplishing goals from some applica-tion domain”. Fig. 4 shows the general interaction framework.

interactive: “of or relating to a program that responds to user activity” (The American Dictionary of the English Language, 4th Ed.),

“of or relating to a two-way electronic or communications system in which re-sponse is direct and continual” (dictionary.com), “reciprocally active; (of a computer or other electronic device) allowing a two-way flow of information between it and a user, responding to the user’s input” (The Concise Oxford Dictionary, 8th ed.)

interactivity: “In computers, interactivity is the dialog that occurs between a human being (or possibly another live creature) and a computer program.” (whatis.com)

(Steuer, 1994) Steuer, J. (1994): Defining virtual reality: Dimensions determining telepresence, in B. F. and M. Levy (Eds.), Communication in the age of virtual reality, Hillsdale (NJ): Lawrence Erlbaum Associates. http://cyborganic.com/People/jonathan/Academia/Papers/Web/definingvr1.html

(Heeter, 1989) Heeter, C. (1989): Implications of New Interactive Technologies for Conceptual-izing Communication, in S. J. L. and J. Bryant (Eds.), Media Use in the Informa-tion Age: Emerging Patterns of Adoption and Consumer Use, Hillsdale (NJ): Lawrence Erlbaum Associates

(Haack, 1995) Haack, J. (1995): Interaktivität als Kenn-zeichen von Multimedia und Hyper-media, in L. J. Issing and P. Klimsa (Eds.), Information und Lernen mit Multimedia, Psychologie Verlags Union, 151-166

(Dix et al., 1998) Dix, A. J., Finlay, J. E., Abowd, G. D. and Beale, R. (1998): Human-Computer Interaction, Harlow: Prentice Hall Europe

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There are many possible methods for providing the input by the user to articulate his/her task, as well as there are many ways of outputting the system’s response, though the visual output on a screen is dominating.

Fig. 4: Interaction framework (Dix et al. 1998, p. 107)

Holzinger (2001, p. 185) distinguishes three different interaction methods:

• descriptive interaction methods, i.e. interaction through linguistic descriptions (symbols, formal and natural lan-guages)

• deictic interaction methods, i.e. interaction through selec-tions by pointing actions (menus, function keys, meta-phoric dialogues)

• hybrid interaction methods Apart form the interaction method, the modality of interaction

must be differentiated. The term modality is generally used to refer to the human perceptual channel or senses for information acquisition, i.e. visual, auditory, haptic, olfactory, and gustatory. For HCI the visual and auditory channels are of major importance (van Mulken 1999). If two different modalities are involved in the information perception, the interface or system is called bimodal. If more than two modalities are involved, the system is analogically called multimodal. To exchange information codes are used. The information to be perceived by a human could be encoded either as text or pictures, i.e. monocodal or in different coding systems (e.g. sound and text) at the same time, i.e. multicodal. Media refers to the physical carriers of information.

Interactions in interactive systems can have a mode. This is not to be mixed up with the term modality. The mode of an interaction dialogue affects the interpretation of the actions. An example is the

(Holzinger, 2001) Holzinger, A. (2001): Basiswissen Multi-media, Band 3, Würzburg: Vogel Buch-verlag

(van Mulken, 1999) van Mulken, S. (1999): User Modeling for Multimedia Interfaces: Studies in Text and Graphics Understanding, Wies-baden: Deutscher Universitäts-Verlag

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form of the mouse pointer depending on the mode of the interac-tion in an application.

Today most interactive systems follow a bimodal direct manipu-lation interaction style which is often referred to as Windows - Icons – Menus - Pointers (WIMP). The initiative and control of this interaction style is clearly on the user side who has several options and often numerous applications simultaneously available (Dix et al. 1998, p. 136). There are definitely many advantages of such an approach. Interactivity means participation of the user, an active part in using the system. Important factors of interactivity are its motivation function that has an impact on the learning effect, i.e. the establishment of an internal mental model and memorability, and its function of individualisation (Haack 1995).

Despite the definitions mentioned above, interactivity is a loose and poorly defined concept. Interactivity certainly has pushed HCI a great leap forward and interactive systems are state of the art in many domains, also in cartography. Crampton (2002) describes a taxonomy of interactive functions in geovisualisation and argues that a highly interactive map provides many of theses functions, whereas a non-interactive map (e.g. a scanned raster map) does not offer any interaction possibilities. Certainly, interactivity is a powerful means for engaging the user. This is especially the case for explorative analysis and learning where interaction is surely important and desired. However, interactivity per se is not neces-sarily a quality feature and not always more efficient. It might take too much time to learn or to achieve a goal by interactive steps. For mobile systems, a certain adaptation seems to be more adequate, since the environment is changing very dynamically. This fact does not allow for too much exploration, since time is usually a critical factor. Interaction in HCI is generally seen as control, as power, though interactivity in a mobile context could rather be regarded as a disadvantage, requiring a lot of user attention and also a lot of additional knowledge about the system handling. Therefore the goal is to reduce the need of continuous control actions by the user without taking from the user the overall power over the system. Another critical issue on the interactive approach for mobile devices is related to its usage. Interactivity is mostly used to compensate for the small displays and not for enhancing the user experience.

(Haack, 1995) Haack, J. (1995): Interaktivität als Kenn-zeichen von Multimedia und Hyper-media, in L. J. Issing and P. Klimsa (Eds.), Information und Lernen mit Multimedia, Weinheim: Psychologie Verlags Union, 151-166


(Crampton, 2002) Crampton, J. W. (2002): Interactivity Types in Geographic Visualization, Cartography and Geographic Information Science 29(2): 85-98.

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The interaction styles with mobile devices are somewhat different from stationary PCs. In general input to the system is executed by a pen and touch-sensitive screen. This allows for pointing and dragging. Text input can be effected by handwriting recognition or pointing on a soft keyboard. Both ways are tedious for longer texts. Output by the system is mainly visual and partially auditory. The latter is still not evolved to its full extent. Thus, the most promis-ing approach seems to be multimodal interactivity. Especially in mobile situations, speech input and output could be helpful. Usability

Many mobile applications ignore the fact that input in mobile devices is limited and slow. The design of mobile services is still very technology driven. The consequence are applications and services with poor usability: “The mobile industry in Europe and the US is to a large extent governed and developed by engineers who have not paid sufficient attention to the target groups of mobile devices. Mobile phones are not aesthetically pleasing enough, navigation is tricky and services are hard to use” (Olsson and Svanteson 2001). Before further investigating this statement it is worth exploring the principles of usability and why it is so im-portant. In the ISO 9241-11 (Guidance on Usability) standard usability is defined as

… the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfac-tion in a specified context of use.

According to this definition usability can express how well the user’s goal is feasible with a product (or service) in a specific con-text. At this place two links to following theories are worth men-tioning: goals are genuinely connected with user activities (see section 2.1.2 on activity theory) and the reference to the context of use is taken up in section 2.1.3 on context. Usability is only one attribute of the overall system acceptability as shown in Fig. 5.

Further reading:

(Shneiderman 1987) Shneiderman, B. (1987): Designing the User Interface, Reading: Addison-Wesley

(Rodden et al. 1998) Rodden, T., Cheverst, K., Davies, N. and Dix, A. (1998): Exploiting Context in HCI Design for Mobile Systems, Proceedings First Workshop on Human Computer Interaction with Mobile Devices, Depart-ment of Computing Science, University of Glasgow, May 21-23, 1998. http://www.dcs.gla.ac.uk/~johnson/papers/mobile/HCIMD1.html

(Olsson and Svanteson, 2001) Olsson, A. and Svanteson, S. (2001): User Intelligence Will Make Mobile Solutions Fly, Whitepaper, Stockholm. http://www.hci.uu.se/~jg/UCD2001/Olsson.pdf

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Fig. 5: System acceptability attributes (Nielsen 1993, p. 25)

Nielsen (1993) separates five attributes for usability – depicted in the usability branch in Fig. 5:

• Learnability: The system should be easy to learn so that the user can rapidly start getting some work done with the sys-tem.

• Efficiency: The system should be efficient to use, so that once the user has learned the system, a high level of produc-tivity is possible.

• Memorability: The system should be easy to remember, so that the casual user is able to return to the system after some period of not having used it, without having to learn every-thing all over again.

• Errors: The system should have a low error rate, so that users make few errors during the use of the system, and so that if they do make errors they can easily recover from them. Further, catastrophic errors must not occur.

• Satisfaction: The system should be pleasant to use so that users are subjectively satisfied when using it; they like it.

HCI literature is rich of hints to solve some of the usability related problems by applying specific interaction paradigms or principles. Dix et al. (1998) point out three major categories of principles to support usability: learnability, flexibility, and robustness. For each category they identify specific principles. For this work, the cate-gory flexibility is the most relevant one. The principles of this cate-gory are: substitutivity; multi-modality; representation multi-plicity; customizability; adaptivity; adaptability. The last two

(Nielsen, 1993) Nielsen, J. (1993): Usability Engineering, London: Morgan Kaufmann - Academic Press


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principles are of major interest for this research and are discussed in section 2.1.4 and chapter 5.

The need to evaluate quality in use has been addressed by several authors, e.g. (Nielsen 1993; van Welie et al. 1999; Carroll 2000; Rosson and Carroll 2002). Regarding the use of mobile geographic information and the arising usability issues only very recently attention in research has been drawn to that field; e.g. (Broadbent and Marti 1997; van Welie and de Ridder 2001; Nivala et al. 2003). Mobile geographic information usage causes some new usability problems. The major usability problems associated with mobility are:

• diverse user activities • diverse usage contexts • changing users • distracted users • heterogeneity of devices • interaction restrictions

While some of these problems are a pure matter of technology, others are related to cognitive abilities. The main reason is that mobility increases the load of cognitive processing. The objective should therefore be to simplify visualisation to such an extent that the user is not forced to think unnecessarily. For Web site design Steve Krug coined the term ‘Don’t Make Me Think!’. According to Krug (2000, p. 11) “It means that as far as is humanly possible, when I look at a Web page it should be self-evident. Obvious. Self-explanatory. I should be able to ‘get it’ what it is and how to use it without expending any effort thinking about it.” In other words, the cognitive effort of the user should be as minimal as possible. Krug’s statement is directed to Web site design. If applied to mobile applications or service design it becomes even more important. In mobile usage situations the amount of stimulation is even larger, the problem of focussing the attention even more serious.

It is obvious that a pure interactive based approach will certainly not meet all usability criteria in mobile usage situations. Empirical studies prove the fact that systems requiring too much attention or too many interactions are not used efficiently or not used at all (The HCI Space). One reason is the ´information overload´. The human brain is only capable to pay attention to a number of five to nine things at the same time. This number is called ´maximum cognitive load´. The cognitive load is generally higher in mobile environments. Another argument is the energy and stress balance: though the cognitive abilities of humans are remarkable and

(van Welie et al., 1999) van Welie, M., van der Veer, G. C. and Eliëns, A. (1999): Breaking Down Usability, Proceedings Interact 99, Edinburgh, Scotland, August, 30 - September, 3. http://www.cs.vu.nl/~martijn/gta/docs/Interact99.pdf

(Carroll, 2000) Carroll, J. M. (2000): Making use: scenario-based design of human-com-puter interactions, Cambridge (MA): MIT Press

(Rosson and Caroll, 2002) Rosson, M. B. and Carroll, J. M. (2002): Usability Engineering: Scenario-Based Development of Human-Computer Interaction: Morgan Kaufmann

(Bradbent and Marti, 1997) Broadbent, J. and Marti, P. (1997): Location aware mobile interactive guides: usability issues, Proceedings The Fourth International Conference on Hypermedia and Interactivity in Muse-ums, Paris, Sept. 1-5, 1997. http://www.ing.unisi.it/lab_tel/hips/hips_pub.htm

(van Welie and de Ridder, 2001) van Welie, M. and de Ridder, G. (2001): Designing for Mobile Devices: a Context-Oriented Approach, Proceedings IBC Conference “Usability for Mobile Devices”, London, UK, May, 9-11

(Nivala et al., 2003) Nivala, A.-M., Sarjakoski, L. T., Jakobsson, A. and Kaasinen, E. (2003): Usability Evaluation of Topographic Maps in Mobile Devices, Proc. 21st Int. Cartogr. Conf., Durban, S. Africa, Aug. 10-16, 2003

(Krug, 2000) Krug, S. (2000): Don't Make Me Think! A Common Sense Approach to Web Usability, Indianapolis (IN): New Riders Publishing

The HCI Space: www.tau-web.de/hci/space/i2.html

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humans are flexible and adaptive, it has to be emphasized that these adaptation efforts generate stress and need extra energy as well as that the error rate increases, i.e. efficiency decreases (The HCI Space). These empirical findings support the theory that in mobile contexts adaptive approaches could be more appropriate. On the other hand, a pure non-interactive system would not work either. For this research, the author therefore proposes a combined interactive-adaptive approach: both adaptation and interaction are included, but there will be a shift from interaction to more adapta-tion. A combined system-user cognition approach is favoured. It is closely related to shared decision making, shared cognition, aug-mented cognition, and amplified cognitive environments. The aim is to support the human cognition by balancing the cognitive load between human user and the system. This idea has been described by many researchers in the field of cartography and GIS. Turk (1993) analyses the cognitive responsibility between the system and the user. Weibel (1991) extends this concept to the amplified intelligence approach in map generalisation. 2.1.2 Activity theory

As pointed out in several publications one approach to overcome the limitations of a pure cognitive science approach in HCI is activity theory (AT). The foundation of AT has been laid by the Russian psychologist Leontjew (Leontjew 1978). The central focus of AT are human activities. In contrast to behaviour activities are always goal bound. Although activities are conducted through individual actions, the activity is the basic unit of analysis: “a minimum meaningful context for individual actions must be included in the basic unit of analysis. This unit is called activity” (Kuutti 1996). AT can be condensed to five basic principles (Kaptelinin et al. 1999):

• Object-Orientedness: “An activity is a form of doing directed to an object, and activities are distinguished from each other according to their objects. Transforming the object into an outcome motivates the existence of an activity. An object can be a material thing, but it can also be less tangible (such as a plan) or totally intangible (such as a common idea) as long as it can be shared for manipulation and transformation by the participants of the activity” (Kuutti 1996, p. 27).

• Hierarchical Structure of Activity: activities follow a struc-ture and hierarchy: “… activities consist of actions or chains of actions, which in turn consist of operations

(Turk, 1993) Turk, A. (1993): The Relevance of Human Factors to Geographical Infor-mation Systems, in D. Medyckyj-Scott and H. H. M. (Eds.), Human Factors in Geographical Information Systems, London: Belhaven Press, 15-31

(Weibel, 1991) Weibel, R. (1991): Amplified intelligence and rule-based systems, in B. P. Butten-field and R. B. McMaster (Eds.), Map Generalization - Making Rules for Knowledge Representations, Harlow: Longman, 172-186

(Leontjew, 1978) Leontjew, A. N. (1978): Activity, con-sciousness and personality, Englewood Cliffs (NJ): Prentice Hall

(Kuutti, 1996) Kuutti, K. (1996): Activity Theory as Potential Framework for Human-Computer Interaction Research, in B. A. Nardi (Ed.), Context and consciousness : activity theory and human-computer interaction, Cambridge (MA): MIT Press, 17-44

(Kaptelinin et al., 1999) Kaptelinin, B., Nardi, B. and Maculay, C. (1999): The Activity Checklist: A Tool for Representing the 'Space' of Context, interactions 6(4): 27-39

Further reading: (Werlen 1988) Werlen, B. (1988): Gesellschaft, Hand-lung und Raum: Grundlagen handlungs-theoretischer Sozialgeographie, Wiesbaden: Steiner

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…”(ibid., p. 30). Whereas actions and operations are con-ducted sequentially, activities can be performed in a parallel way. The position in the hierarchy is not static (Fig. 7). An activity can become an action or even an operation and vice-versa.

• Internalization and Externalization: AT distinguishes between external and internal activities. External activities are directed to physical objects outside the mind, but can be internalised. This allows for example for interacting (mentally) with reality without manipulating the real objects. This fact helps to choose from different possible actions by simulating their effects first. The opposite is also possible: internal activities can also be ex-ternalised.

• Mediation: tool mediation is a central issue in AT. After AT tools enfold their power when they are used and when there is the knowledge how to use them (Fig. 6). “An activity always contains various artefacts (e.g. instruments, signs, procedures, machines, methods, laws, forms of work organization)” (ibid., p. 26).

• Development: activities cannot be understood at a single point in time, but have to consider the ‘history’ of the activity.

An activity is a sequence of actions conducted by a human being aimed at achieving a certain objective. This objective could be solving a problem or a task. An action has therefore always an intentional character (Bødker 1991).

Fig. 6: Elements of activity theory (after Engeström 1987)

An action itself is composed of one or several operations con-ducted unconsciously (Bødker 1991): “Each action that a human being carries out also has operational aspects (how is it done). The operational aspects of actions are implemented through a series of

(Bødker, 1991) Bødker, S. (1991): Through the Interface: A Human Activity Approach to User Interface Design, Hillsdale (NJ): Lawrence Erlbaum Associates

(Engeström, 1987) Engeström, Y. (1987): Learning by expanding: An activity theoretical approach to developmental research, Helsinki: Orienta-Konsultit

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operations. … Actions can be operationalized that is turned into operations. Operations can be conceptualized. Conceptualization means to articulate for oneself what is otherwise self-evident.“ This different levels and the operationality is shown in Fig. 7.

Fig. 7: Levels of activity (Kuutti 1996, p. 30)

Actions are planned by human beings to change a situation or an object to achieve the intended goal. In mobile situations user goals could be orientation, finding persons or objects, finding the way to an object, etc. Another important aspect of human activities is the fact that they are always embedded in a context and performed in a specific role. An individual can perform the same action in dif-ferent contexts and roles (see Fig. 6). This context shapes the activities and vice-versa. The activity context constrains the plan-ning of actions before they are executed: “Before an action is performed in the real world, it is typically planned in the con-sciousness using a model. The better the model, the more success-ful the action. This phase is called orientation” (Kuutti 1996, p. 31). Fig. 8 shows the activity process model.

To summarise the basic concepts of AT, activities are goal bound and object-directed series of actions taking place in a specific con-text using means (artefacts, tools).

Fig. 8: Process model of activity theory (adapt. from Werlen 1988, p. 13)

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2.1.3 Context

In the last section it has been stated that activities are always per-formed in a context. Thus it is crucial to be aware of the basic concepts of context for understanding user activities. Unfortu-nately context is a word with many meanings – depending on ‘context’.

Schilit et al. (1995) define context as about where you are, who you are with, and what resources are nearby. In (Ryan et al. 1997) context is defined as the user’s location, environment, identity and time. One of the most adopted definitions of context in the field of context-awareness is the one from Dey and Abowd (1999, p. 3f.):

Context is any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and applications themselves.

The authors further distinguish between primary context and secondary context elements. Primary context elements are place, time, identity, and activity. The primary context elements can work as indices to secondary elements (e.g. appointments, weather conditions). Place as manifested in the term location based service is of utmost importance as a context parameter for geographic information. Place is the more general term widely used in cartography. Location refers to a placement of the mathematical definition relative to natural and artificial features (Krakiwsky et al. 1990); location is a reference to a position obtained by geoloca-tion under the usage of a location fixing scheme. Positioning technologies are covered in section 2.2.1.

A similar context concept is proposed by van Welie and de Ridder (2001). Three elements are more or less identical with the elements from Dey and Abowd: identity, place, and time. The fourth element is device. This element describes the technical char-acteristics of mobile devices that can be important for information delivery and presentation. Since context is the central issue in mobile geovisualisation services, it is further examined in section 4.2.3.

(Schilit et al., 1995) Schilit, B., Adams, N. and Want, R. (1995): Context-Aware Computing Applications, Proceedings Workshop on Mobile Computing Systems and Applica-tions, Santa Cruz (CA), December 8-9, 1994, IEEE Computer Society Press

(Ryan et al., 1997) Ryan, N., Pascoe, J. and Morse, D. (1997): Enhanced Reality Fieldwork: the Context-Aware Archaeological Assistant, in S. Exxon (Ed.), Computer Applications in Archaeology

(Dey and Abowd, 1999) Dey, A. K. and Abowd, G. D. (1999): Towards a Better Understanding of Context and Context- Awareness, Tech-nical Report, GIT-GVU-99-22, Georgia Institute of Technology, Atlanta (GA)

(Krakiwsky, 2002) Krakiwsky, E. J., Lachapelle, G. and Schwarz, K. P. (1990): Assessment of Emerging Technologies for Future Navi-gation Systems in the Canadian Transportation Sector, Contract Report TP 10155-E, Research and Development Directorate, Transport Canada, Ottawa. Publ. 60007, Department of Surveying Engineering, The University of Calgary, Calgary

(van Welie and de Ridder, 2001) van Welie, M. and de Ridder, G. (2001): Designing for Mobile Devices: a Context-Oriented Approach, Proceedings IBC Conference “Usability for Mobile Devices”, London, UK, May, 9-11

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2.1.4 Adaptation

Systems without interaction possibilities are commonly called batch systems or non-interactive systems. Systems that can be changed by the user are flexible or malleable systems. The latter rely on adaptation of the system. The term adaptation is widely used in science and technology. In biology adaptation refers to changes in relation to environmental conditions. Not all things can be adapted or are able to adapt themselves. Hence, adaptable refers to the fact that adaptation is in principle possible. An adaptable system provides the user tools that make it possible for him/her to change the system characteristics (Oppermann 1994). The quality of being adaptable is called adaptability. Adaptation in a computer system is the adjustment of parameters through users, whereas adaptivity is the automatic adaptation of the system to users or a self-adaptation. An adaptive system is capable of changing its own characteristics automatically according to the user’s needs (Oppermann 1994). An adaptable system can be changed by the user in an interactive way, i.e. by explicit interfer-ence. In an adaptive system the interference is implicit.

Apart from these more general notions of adaptation there are a few special cases of adaptation:

• Personalisation: is basically the adaptation of something to a user, or “whenever something is modified in its con-figuration or behaviour by information about the user, this is personalisation” (Searby 2003, p. 13).

• Individualisation: is often used as a synonym of personal-isation, though individualisation is more general, i.e. individualisation could be related to a group (of persons).

• Localisation: is the adaptation of a software, i.e. in general the user interface, to a specific region, i.e. mostly to a lan-guage area and character setting.

• Customization: is the adaptation of a product or service to a customer or user.

Personalisation and customisation are terms often used in mar-keting, whereas localisation is vocabulary of software engineering.

For an overview of adaptation research refer to (Browne et al. 1990; Schneider-Hufschmidt et al. 1993; Oppermann 1994; Blank 1996). For this work three main threads of adaptation research are of importance: adaptive systems, adaptive user interfaces, and adaptive hypermedia. Most of the following theoretical concepts are related to adaptive user interfaces.

(Oppermann, 1994) Oppermann, R., (Ed.) (1994): Adaptive User Support: Ergonomic Design of Manually and Automatically Adaptable Software, Computers, Cognition, And Work, Hillsdale (NJ): Lawrence Erlbaum Associates

adaptation: “(1) the act or process of adapting or being adapted or the state of being adapted; adjustment (2) something that is produced or created by adapting something else (3) something that is changed or modified to suit new condi-tions or needs” (Collins English Dictionary, 3rd Edition)

“The act of adaptation, adapting, means to fit, adjust, make suitable for a purpose, alter or modify | to change (something or yourself) to suit different conditions or uses” (dictionary.cambridge.org) “To make suitable to or fit for a specific use or situation” (www.dictionary.com)

adaptable: “(1) able to adapt oneself to new conditions; (2) that can be adapted” (The Concise Oxford Dictionary, 8th ed.)

(Searby, 2003) Searby, S. (2003): Personalisation - an overview of its use and potential, BT Technology Journal 21(1): 13-19

(Browne et al., 1990) Browne, D., Totterdell, P. and Norman, M., (Eds.) (1990): Adaptive User Inter-faces, Computers and People Series, London: Academic Press

(Schneider-Hufschmidt et al., 1993) Schneider-Hufschmidt, M., Kühme, T. and Malinowski, U., (Eds.) (1993): Adaptive User Interfaces: Principles and Practice, Human Factors in Information Technology, Amsterdam: North-Holland

(Blank, 1996) Blank, K. (1996): Benutzermodellierung für adaptive interaktive Systeme: Architektur, Methoden, Werkzeuge und Anwendungen, Sankt Augustin: Infix

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Structure of adaptive systems

The basic structure of any adaptive system is based on an adaptive object that is adapted to an adaptation target through an adap-tation method (Fig. 9). The adaptation method will need information about the adaptation target.

Fig. 9: Basic principle of adaptation systems

Oppermann (1994, p. 6f.) distinguishes three major elements of adaptive systems:

• afferential component of adaptivity: this component is responsible for gathering information about user interaction and system responses and finding patterns on different levels of interaction

• inferential component of adaptivity: in this component decisions about if and how system modifications, i.e. adaptations, are made based on analysing captured user information

• efferential component of adaptivity: this component effects the system’s behaviour modifications

Along with the discussion of the structure of an adaptive system the question arises when exactly a system should be called adap-tive. This question relates to the degree of adaptivity (Fig. 10).

Fig. 10: Adaptation spectrum

Considering Fig. 10 one could argue that an adaptive system must be completely adaptive, i.e. a system on the left edge of the adaptation spectrum. For this work an adaptive system is a system

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including some adaptive functions and behaviour, i.e. laying left from the middle of the spectrum.

According to Holzinger (2001, p. 206) adaptive methods (which can be extended to adaptation in general) can be analysed in the following four different dimensions: adaptation means, adaptation information, adaptation process, and adaptation goal. Table 1 shows other terminologies for adaptation dimensions. The term ‘adaptive methods’ is to some extent ambiguous. Although in the sense of Holzinger it means methods related to adaptive behav-iour, it could also mean methods that are themselves adaptive. For the purpose of this work, the term is used in the sense of a method for adaptation. (Holzinger 2001)

(Dietrich et al. 1993)

(Karagianni-dis et al. 1995)

(Brusilovsky 1996)

(Thévenin and Coutaz 1999)

(Alatalo and Peräaho 2001)

Adaptive Hypermedia

Adaptive user inter-faces


Adaptive Hypermedia


Adaptive Hypermedia

adaptation adaptivity adaptivity means constituents constituents what to

adapt? means transformants

information information to be con-sidered

determinants to what to adapt?

target adaptors

process strategies rules how to adapt?

heuristics

goal goals goals why to adapt?

Table 1: Terminology of adaptation dimensions

As Table 1 reveals, there are some semantic differences in the terminology, but consensus can be observed regarding the main structural components. Depending on the system, different objects are adapted, for instance the user interface, hypermedia content or the link structure. The target of the adaptation can also vary. In a learning system it is primarily the user, in a mobile system it could be the context of usage. Taxonomy of adaptive systems

In literature many attempts of conceptualising adaptation can be found. Some of these attempts resulted in taxonomies of adaptive systems. A basic distinction can be made between adaptive and adaptable systems. Table 2 summarises the major distinguishable elements proposed by Fischer (2001, p. 11).

Holzinger, 2001) Holzinger, A. (2001): Basiswissen Multi-media, Band 3, Würzburg: Vogel Buchverlag

(Dietrich et al., 1993) Dietrich, H., Malinowski, U., Kühme, T. and Schneider-Hufschmidt, M. (1993): State of the Art in Adaptive User Inter-faces, in M. Schneider-Hufschmidt, T. Kühme and U. Malinowski (Eds.), Adap-tive User Interfaces, Amsterdam: North-Holland

(Karagiannidis, 1995) Karagiannidis, C., Koumpis, A. and Stephanidis, C. (1995): Supporting Adaptivity in Intelligent User Interfaces: The case of Media and Modalities Allocation, Proceedings ERCIM Working Group on User Interfaces for All Work-shop "Towards User Interfaces for All: Current Efforts and Future Trends", Heraklion, Greece, October 30-31

(Brusilovsky, 1996) Brusilovsky, P. (1996): Methods and techniques of adaptive hypermedia, User Modeling and User-Adapted Interaction 6(2-3): 87-129

(Thévenin and Coutaz, 1999) Thévenin, D. and Coutaz, J. (1999): Adaptation and Plasticity of User Inter-faces, Proc. i3-spring99Workshop on Adaptive Design of Interactive Multimedia Presentations for Mobile Users, Barce-lona. http://research.nii.ac.jp/~thevenin/papers/I3Workshop1999/I3Workshop99.pdf

Alatalo and Peräaho, 2001) Alatalo, T. and Peräaho, J. (2001): A Modelling Method for Designing Adap-tive Hypermedia, Proceedings Eight International Conference on User Mod-eling (UM2001) - Third Workshop on Adaptive Hypertext and Hypermedia, Sonthofen, Germany, July 13-17, 2001

(Fischer, 2001) Fischer, G. (2001): User Modeling in Human-Computer Interaction, User Modeling and User-Adapted Interaction (UMUAI) 11(2): 65-86

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Adaptive Adaptable Definition dynamic adaptation by the

system itself to current task and current user

user changes (with substantial system support) the function-ality of the system

Knowledge

contained in the system; projected in different ways

knowledge is extended

Strengths little (or no) effort by the user; no special knowledge of the user is required

user is in control; user knows her/his task best; system knowledge will fit better; suc-cess model exists

Weaknesses user has difficulty develop-ing a coherent model of the system; loss of control; few (if any) success models exist (except humans)

systems become incompati-ble; user must do substantial work; complexity is increased (user needs to learn the ad-aptation component)

Mechanisms required

models of users, tasks, and dialogs; knowledge base of goals and plans; powerful matching capabili-ties; incremental update of models

layered architecture; domain models and domain-orienta-tion; ‘back-talk’ from the system; design rationale

Application Domains

active help systems, critiqu-ing systems, differential descriptions, user interface customization, information retrieval

information retrieval, end-user modifiability, tailorability, filtering, design in use

Table 2: Adaptable and adaptive systems (Fischer 2001)

On the premise that the functions and its parameters available in an interactive system are of a finite number, no principal difference in the outcome of a user adapting the system and of the system adapting itself can be implied. The degrees of freedom stay the same for both the user and the system, since the user only uses the system’s functionality to achieve his/her goals. The problem for an adaptive system is rather capturing information for adaptation and deferring the user’s intentions. This knowledge is available to the user, but not a priori to the system.

The distinction between adaptable and adaptive systems or interfaces certainly is the most predominant one, but there are many more grades of flexible systems. Totterdell and Rautenbach (1990, p. 74) suggested the following taxonomy of adaptive sys-tems:

• adaptable/ tailorable • adaptive • self-regulating • self-mediating • self-modifying

(Totterdell and Rautenbach, 1990) Totterdell, P. and Rautenbach, P. (1990): Adaptation as a problem of design, in D. Browne, P. Totterdell and M. Norman (Eds.), Adaptive User Interfaces, London: Academic Press, 59-84

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Dietrich et al. (1993, p. 15) discern four stages in the adaptation process: initiative, proposal, decision, and execution. Furthermore they distinguish between the two possible agents in these four stages: the user and the system. Both can be the active part in any of the four stages. In the example portrayed in Fig. 11 the system initiates, proposes, and executes an adaptation after it has been accepted by the user.

Fig. 11: Agents involved and stages in the adaptation process (Dietrich et al. 1993)

Combining all four stages with the two agents, results in 42 = 16 possibilities. Not all of them are really sensible in practice. Fig. 12 depicts the most important adaptation types. The spectrum of pos-sible adaptation types reaches from adaptable to (self)adaptive. For this work self-adaptation and user controlled self-adaptation are the two types of most interest. The case depicted in the lower left corner of Fig. 12, adaptation, describes an interactive, adaptable system where the user has the full control, but also all responsi-bility to change the system.

Fig. 12: Different types of adaptation (Dietrich et al. 1993, p. 17)

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Motivation for adaptive systems

Before going into the details of adaptation, a justification of this approach and the rationale for adaptive behaviour are presented. In general, an adaptive approach should improve usability, ease our daily life with computer systems, change the role of the com-puter as a tool for humans rather than humans being slaves of technology: “It is widely believed that ‘everyone should be com-puter literate’ and as a consequence vast human and financial resources are being expended internationally on training indi-viduals to adapt to using computers within their lives. The premise … is that computers should be user literate” (Browne et al. 1990, preface). A similar understanding, i.e. a system adapting to the user, can be discovered in (Oppermann 1994, p. 4): “The goal of adaptive systems is to increase the suitability of the system for spe-cific tasks; facilitate handling the system for specific users, and so enhance user productivity; optimize workloads, and increase user satisfaction”. Almost the same statement has been made by Sanderson and Treu (1993, p. 245), though they put the focus on the user interface: “That is, depending on the needs of a particular user to whom the interface is to adapt, the adaptation behaviour should be facilitative, such as by enabling the user to complete tasks more quickly or with less knowledge and effort”.

Common to all statements is the focus on usability and a shift from the adaptation responsibility towards the (computer) system. Timing of adaptivity

The timing of adaptation is basically related to the question when and how often adaptation will take place. Dietrich et al. (1993, p. 23f.) identify three different timings: before, during, and between usage sessions. If adaptation occurs during sessions, they further distin-guish between continuous adaptation, adaptation in special situations, and adaptation after or before predefined functions. A similar distinction is made by Leutner (1995). Macro adaptation designates the occasional adaptation, normally before system usage. On the other hand, micro adaptation is the adaptivity of a system in very short intervals during usage.

Related to the question of timing the adaptation is the question of what triggers the adaptation. Alatalo and Paräaho (2001) mention two basic types of adaptivity: adapting to difference and adapting to change, where difference relates to time-independent objects (e.g. different user, different device, different location) and change relates to objects that change over time (e.g. outdoor temperature). Of course this distinction is not always absolutely clear. A user can


Oppermann, 1994) Oppermann, R., (Ed.) (1994): Adaptive User Support: Ergonomic Design of Manually and Automatically Adaptable Software, Computers, Cognition, And Work, Hillsdale (NJ): Lawrence Erlbaum Associates

(Sandersopn and Treu, 1993) Sanderson, P. D. and Treu, S. (1993): Adaptive User Interface Design and Its Dependence on Structure, in M. Schneider-Hufschmidt, T. Kühme and U. Malinowski (Eds.), Adaptive User Inter-faces: Principles and Practice, 10, Amsterdam: North-Holland, 241-267


(Leutner, 1995) Leutner, D. (1995): Adaptivität und Adaptierbarkeit multimedialer Lehr- und Informationssysteme, in L. J. Issing and P. Klimsa (Eds.), Information und Lernen mit Multimedia, Weinheim: Psychologie Verlags Union, 139-149

Alatalo and Peräaho, 2001) Alatalo, T. and Peräaho, J. (2001): A Modelling Method for Designing Adap-tive Hypermedia, Proceedings Eight International Conference on User Mod-eling (UM2001) - Third Workshop on Adaptive Hypertext and Hypermedia, Sonthofen, Germany, July 13-17, 2001

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for instance, though only slowly, change over time. This distinction leads to the two basic triggers: difference and change. The difference or change can be of a quantitative (e.g. movement speed) or of a qualitative (e.g. activity) dimension. Similarly change can be neutral, an extension or a limitation of possibilities (e.g. limitation through reduced bandwidth). Sanderson and Treu (1993, p. 246) differentiate three conditions for adaptation:

• locality: where exactly should changes be made? • granularity: at what level of generality or specificity

within a locality should changes be made? • timing: the triggering of adaptation can be independent of

a particular setting (locality and granularity), but depends on other circumstances

These three conditions can serve as criteria for making adaptation decisions. Level of adaptivity

Depending on the domain different objects are available for adap-tation. In a hypermedia system, for instance, the content or the link structure can be adapted. In an interactive system, the interaction style or the availability of functions could be adapted. These adaptation objects are not all of the same type and on the same level. Depending on the type of information Dietrich et al. (1993, p. 27) distinguish two basic levels of adaptation:

• logical/invisible/symbol level • physical/visible/signal level

These levels correspond more or less to the two basic layers (physical and symbolic) of interaction in HCI discussed in section 2.1.1. A further refinement separates goals, tasks, semantic, syn-tactic, and lexical level. A similar differentiation was proposed by Stephanidis and Savidis (2001, p. 42) who distinguish three levels of interaction on which adaptation could be effected:

1) semantic level of interaction (e.g. by employing different metaphors to convey the functionality and facilities of the underlying system)

2) syntactic level of interaction (e.g. by deactivating alternative dialogue patterns, such as ‘object-function’ versus ‘function-object’ interaction sequencing)

3) lexical level of interaction (e.g. grouping and spatial arrangement of interactive elements, modification of presentation attributes, alternative input/output devices)

(Sandersopn and Treu, 1993) Sanderson, P. D. and Treu, S. (1993): Adaptive User Interface Design and Its Dependence on Structure, in M. Schneider-Hufschmidt, T. Kühme and U. Malinowski (Eds.), Adaptive User Inter-faces: Principles and Practice, 10, Amsterdam: North-Holland, 241-267

(Stephanidis and Savidis, 2001) Stephanidis, C. and Savidis, A. (2001): Universal Access in the Information Society: Methods, Tools, and Interaction Technologies, Universal Access in Infor-mation Society 1: 40-55

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Methods of adaptation

Basic adaptation methods (in user interfaces) are: enabling, switching, reconfiguring, and editing (Cockton 1987) in (Dietrich et al. 1993, p. 28). Enabling refers to the activation or deactivation of components or features. Switching means the selection of prede-fined configuration settings. Reconfiguring refers to modification using predefined components. Editing means the adaptation with-out any restrictions concerning components. An even broader classification distinguishes methods adapting presentation or communication and methods adapting functionality or interaction. Problems with adaptivity

General problems of adaptive systems are the lack of control and data protection (Browne et al. 1990, p. 208f.). Even if a system adapted itself perfectly and to the user’s satisfaction, it could be unacceptable for the user due to psychological reasons. The feeling of being in control, the feeling of power over the machine is very strong and important. This fact is closely related to the second problem: data protection or privacy. If the user does not know and understand which information is stored about him and where it is stored and who will have access to it, even a perfect system based on that knowledge would probably not find any acceptance. A system that adapts in any way to the user, e.g. to preferences, skill, or current location, needs information about the user or related facts. Without this information adaptivity is not possible. Naturally many users feel reluctant to give away personal information. Appropriate means to minimise the chance for misuse have to be developed. They are also needed for other applications like e-commerce. If there are mechanisms to guarantee data privacy and the user is convinced the service provides a substantial utility through the adaptation, the privacy issue can be softened.

However, a further problem that might arise in relation to adap-tation has to do with utility. Utility is often connected to efficiency, more precisely an increasing of efficiency. In technology use the opposite is often the case, the so called ‘rebound effect’. A rebound effect is the fact that an efficiency improvement was initiated with the intention to reduce the amount of input, but this effect does not happen and instead the output increases (Hilty et al. 2003, p. 127). In a study on the effects of pervasive computing on health and environment the authors state that an efficient navigation in the market of leisure activity choices is of enormous indirect benefit (ibid., p. 135f.). LBS can help in an efficient usage of these leisure options. Many trips will become obsolete. A rebound effect with



(Hilty et al., 2003) Hilty, L., Behrendt, S., Binswanger, M., Bruinink, A., Erdmann, L., Fröhlich, J., Köhler, A., Kuster, N., Som, C. and Würtenberger, F. (2003): Das Vorsor-geprinzip in der Informationsgesellschaft: Auswirkungen des Perva-sive Computing auf Gesundheit und Umwelt, TA 46/2003, TA-Swiss, Zentrum für Technologiefolgen-Abschätzung, Bern. http://www.ta-swiss.ch/www-remain/reports_archive/ publications/ 2003/030904_PvC_bericht.pdf

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efficient information and communication adapted to the context results through a possible overkill of intransparent information offers. The gain of time efficiency through more focussed informa-tion might be compensated by the increased effort for judging this information (trustworthiness, hidden motivations, etc.). 2.1.5 Inter-relationships of relevant theories and their appli-cations in cartography

In the nineties AT has been discovered for the field of HCI, e.g. (Bødker 1991; Nardi 1996a). It has been recognised that a pure cog-nitive approach in HCI does not and probably cannot solve all problems of using computer systems, because it is focussed on how the system is actually used. Most cognitive approaches examine a very low level of interaction, for instance the GOMS (Goals, Operations, Methods, and Selection) model. While these methods give certain insight in interaction processes, they lack information about context. AT introduced the notion of the com-puter as a mediating tool. By understanding the use of computers as actions, the context and intention of use are introduced in the analysis. This helps to understand why computers are used and which goals the user has and can explain some misunderstandings and misconceptions in the design of user interfaces. Since car-tography nowadays is computer based and an interface to the map is involved or the map itself is the interface to further information, it is logical that AT has found its way to cartography.

AT is important for cartography when studying the usage of maps. Using a map can be understood as an action and is thus open to AT. There are two major applications of AT to cartogra-phy. The first concentrates on the usage of maps for spatially related actions. Such actions could be planning or route finding. To achieve the action goals the usage of maps is necessary. The second is concerned with actions within a cartographic information sys-tem, i.e. with actually using maps to solve spatial problems, answer spatial questions or meet information needs. The second understanding is closely related to the relationship of HCI and AT, though there are unique characteristics in the cartographic domain. Parts of AT have been studied in the field of map usage. In this context different map functions or map usage goals have been identified (cf. Witt 1979; Ogrissek 1987). Map use tasks have been described in (Gluck 1996; van Elzakker 2001). A more comprehen-sive concept strongly following AT has been proposed by Bollmann (1996). A good overview and evaluation of these dif-ferent activity oriented concepts and approaches in cartography is

(Bødker, 1991) Bødker, S. (1991): Through the Interface: A Human Activity Approach to User Interface Design, Hillsdale (NJ): Lawrence Erlbaum Associates

(Nardi, 1996a) Nardi, B. A. (1996a): Context and consciousness: activity theory and human-computer interaction, Cambridge (MA): MIT Press

(Witt, 1979) Witt, W. (1979): Lexikon der Karto-graphie, Wien: Deuticke

(Ogrissek, 1987) Ogrissek, R. (1987): Theoretische Karto-graphie, Gotha: VEB Hermann Haak

(Gluck, 1996) Gluck, M. (1996): Text, Maps, and User's Tasks, in L. C. Smith and M. Gluck (Eds.), Geographic Information Systems And Libraries: Patrons, Maps, And Spatial Information, 151-172

(van Elzakker, 2001) van Elzakker, C. (2001): Map Use Tasks in Regional Exploratory Studies, Proc. 20th Internat. Cartographic Conference, Beijing, China, August 6-10, 2001

(Bollmann, 1996) Bollmann, J. (1996): Kartographische Modellierung - Integrierte Herstellung und Nutzung von Karten-systemen, Kartographie im Umbruch. Tagungsband zum Kartographenkongress Interlaken 1996, Interlaken

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presented by Dransch (2001a; 2001b). Her research focuses on the activities in HCI and the conception of computer systems as medi-ating tools. More recent research on exploratory geovisualisation is taking a similar approach (Fuhrmann and Kuhn 1999; Fabrikant 2001). However, for this research the focus is on supporting user activities during mobility in the physical space and more specifi-cally on the activity context itself. Hence, for this research a particular flavour of AT, the activity-context oriented approach is considered as useful.

Research on ‘cartographic work graphics’ first introduced by Bollmann (1996) and further investigated by Heidmann (1999) is strongly connected to AT and to the understanding of adapted geovisualisation proposed in this dissertation. Cartographic work graphics comprises all possible ways of graphic support of elec-tronic map usage and combines model approaches for a task and user oriented modelling of cartographic media. Map use is under-stood as a goal directed process of visual cognitive operations. The premise of cartographic work graphics is to support these visual cognitive operations adequately to lead to a more effective map usage and thus information gain. Technically cartographic work graphics can be connected to the original map graphic or be super-imposed. The cartographic work graphics principally distinguishes three support forms controlling the use of cartographic work graphics according to specific communication goals and communication situations: a) the variation and specific orientating of graphic design means in the map, b) through an addition of particularly motivating or associative perceivable signs or sign patterns, and c) through a change of multimedia information offer (Heidmann 1999, p. 52f.).

Knapp (1995) proposes a general task model for the visualisation of geographic data. At the low level four visual operators are dis-cerned: identify, locate, compare, and associate. A similar approach is taken by Zhou (1999) who isolates visual tasks for the automated generation of visual discourse. Visual tasks are understood as a middleware abstraction between high-level presentation intents and low-level visualisation techniques. These visual tasks are described in further detail in section 4.2.6. Both approaches separate the goals of visualisation (e.g. inform or explore) from the actual tasks of visualising to achieve these goals or to solve the problem.

(Dransch, 2001a) Dransch, D. (2001a): Handlungsori-entierte Mensch-Computer-Interaktion für die kartographische Informationsver-arbeitung in Geo-Informationssystemen, Habilitationsschrift, Fachbereich Geowis-senschaften, Freie Universität Berlin

(Dransch, 2001b) Dransch, D. (2001b): User-Centred Human-Computer Interaction In Carto-graphic Information Processing, Proceedings 20th International Carto-graphic Conference, Beijing, China, August, 6 - 10, 2001

(Fabrikant, 2001) Fabrikant, S. I. (2001): Building Task-Ontologies for GeoVisualization - Position Paper, Proceedings ICA Commission on Visualization and Virtual Environments Pre-Conference Workshop on Geovisualization on the Web, Beijing, China, August, 3-4, 2001

(Fuhrmann and Kuhn, 1999) Fuhrmann, S. and Kuhn, W. (1999): Interface Design Issues For Interactive Animated Maps, Proceedings 19th Int. Cartographic Conf., Ottawa, August 14-21, 1999

(Heidmann, 1999) Heidmann, F. (1999): Aufgaben- und nutzerorientierte Unterstützung karto-graphischer Kommunikationsprozesse durch Arbeitsgraphik: Konzeptionen, Modellbildung und experimentelle Untersuchungen, Herdecke: GCA-Verlag

(Kanpp, 1995) Knapp, L. (1995): A task analysis approach of the visualization of geographic data, in T. L. Nyerges, D. M. Mark, R. Laurini and M. J. Egenhofer (Eds.), Cognitive aspects of human-computer interaction for geographic information systems, NATO ASI Series, Serie D: Behavioural and Social Sciences, 83, Dordrecht, 355-371

(Zhou, 1999) Zhou, M. X. (1999): Automated Genera-tion of Visual Discourse, Dissertation, Graduate School of Arts and Sciences, Columbia University

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The concern of this research are activities related to the mobile usage of maps in everyday life and thus the focus is more on user activities in geo-space. Solutions need to address immediate user needs within that mobile context and support everyday activities. Since ancient times one of the inherent functions of an everyday map has been to promote mobility. In spite of diversified devel-opments of map types (topographic map, thematic map, atlas information systems) this function remains unchanged. This no-tion is supported by Fuhrmann and Kuhn (1998) who coined the term everyday map:

We extend the classic notion of a map to ‘everyday maps’, be-cause we believe web-based maps will become available to anyone and will soon function as the public sources of spatio-temporal information for everyday purposes like wayfinding, shopping, dining out, and travelling. It appears justified to introduce the term to ‘everyday maps’, because the contents and functions of these media cannot be explained and defined using traditional map definitions. … Thus, an everyday map is ‘a geographical image of the environment which is suitable for ordinary days or routine occasions’. At the same time, the term ‘everyday map’ derives from Don Norman’s discussion of the design of everyday things (Norman 1988), particularly with respect to the notion of affordances.

A typology of everyday situations grouped in the categories work, home, town, and on the road can be found in (McCullough 2001, p. 344).

The definition of everyday maps perfectly fits the idea of maps for mobile environments. The reference to suitability for everyday occasions introduces the importance of the relevance concept. The importance for a model of information needs based on geographic relevance is emphasized by Raper et al. (2002, p. 44). They name the sense-making methodology as a potential framework for this purpose (sense-making methodology will be explained in section 4.2.4).

Other valuable theories bringing together context theory, activity theory, and cognitive theory respectively are situated action (Suchman 1987; Nardi 1996b) and situated cognition (Clancey 1997). Both approaches share the idea that all human cognitive processes and activities are always embedded in a specific situa-tion and that they can only be understood if this situation is known.

(Fuhrmann and Kuhn, 1998) Fuhrmann, S. and Kuhn, W. (1998): The Design of Everyday Maps, Proceedings Workshop of ICA Commission on Visu-alization meeting, Warszaw, Poland, May, 1998

(McCullough, 2001) McCullough, M. (2001): On Typologies of Situated Interaction, Human-Computer Interaction 16: 337-349

(Raper et al., 2002) Raper, J., Dykes, J., Wood, J., Mountain, D., Krause, A. and Rhind, D. (2002): A framework for evaluating geographical information, Journal of information science 28(2): 39-50

Suchman, 1987) Suchman, L. A. (1987): Plans and situated actions - The problem of human-machine communication, Cambridge: Cambridge University Press

(Nardi, 1996b) Nardi, B. A. (1996b): Studying Context: A comparison of Activity Theory, Situated Action Models, and Distributed Cogni-tion, in B. Nardi (Ed.), Context and consciousness: activity theory and human-computer interaction, Boston (MA): MIT Press, 69-102

(Clancey, 1997) Clancey, W. J. (1997): Situated Cogni-tion, Cambridge: Cambridge University Press

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Since the purpose of this thesis is to establish a framework for mobile cartography and adaptive geovisualisation, the primary focus is on context in the realm of context-aware systems. The objective is to extend the concept of a context-aware system with cognitive theory, AT, and adaptation methods for cartography in mobile environments. This combinational approach is elaborated in chapter 4, where these theories are melted in a new and com-prehensive framework for geovisualisation in mobile envi-ronments. For this work the term geovisualisation is used rather than map. Geovisualisation has been introduced to extend the con-cept of mapping from a pure communication-oriented means towards an exploratory instrument and visual thinking. As explained earlier this understanding of the term is not the focus in this research. However, the traditional concept of a map will not satisfy the requirements of presenting geographic information on mobile devices either. Therefore geovisualisation is used here to cover all forms of presentations of geographic information, i.e. maps, map-like representations, multimedia, even text or audio elements.

2.2 Technical background The focus of this research is not on technology. Most technological issues are off the field of cartography and are advancing so fast that their coverage in a thesis seems almost worthless. However, it is necessary to set up the basic technology context of this work and the interfaces to related fields. A good overview of the current technologies relevant to visualisation of geographic information is given in (Buckley et al. 2000). In general, the technologies described in the following are assumed available and functioning. The goal of this section is to describe the state of the art in mobile computing and its related fields which govern the thoughts on new methods and to identify the part of technology which seems to be invariant over the next few years and hence directly relevant for this work. Fig. 13 illustrates the relationship between the dif-ferent technologies and mobile cartography and refers to the section where they are discussed in more detail.

(Buckley et al., 2000) Buckley, A. R., Gahegan, M. and Clarke, K. (2000): Geographic visualization as an emerging research theme in GIScience, Research proposal, University Consortium for Geographic Information Science. http://www.ucgis.org/priorities/research/research_white/2000%20Papers/emerging/Geographicvisualization-edit.pdf

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Fig. 13: Relevant technologies for mobile cartography

2.2.1 Mobile computing

A good introduction to the topic of mobile computing and related fields is presented in (Stanton 2001). The pioneer of mobile com-puting, Mark Weiser, was one of the first to sketch a vision of new kinds of computing after the era of the PC (Weiser 1991). Apart from mobile computing (Imielinski and Korth 1996; Alatalo et al. 2001) several partly related concepts can be found in literature: nomadic computing (Specht and Oppermann 1999) – ubiquitous computing (Weiser 1991; Abowd and Mynatt 2000) – pervasive computing (Hansmann et al. 2001) – embedded computing (Want et al. 2002) – everyday computing (Mynatt 1999) – invisible com-puting (Norman 1998). Mobile and nomadic computing refer to the possibility of using computing during mobility as opposed to traditional stationary desktop based computing. The other catego-ries go a step further in the sense that computing will be available almost everywhere embedded in any kind of everyday object and moving around computing devices for having access to computing at different places will become obsolete. The ultimate stage is the vision of invisible computing. Strongly connected to the field of mobile computing are the aforementioned context-aware systems. Mobile devices

The actual computing hardware in the range of this work has to allow mobile information access. Norman (1998) calls such devices information appliances. Yet, this term also refers to ubiquitous information access, i.e. embedded technology. For the scope of this work mainly Personal Digital Assistants (PDA) and Smartphones are of interest. The term PDA has been created by John Sculley in 1992 when he was with Apple. In 1993 Apple launched the first

Mobile computing: (Stanton, 2001) Stanton, N. A. (2001): Introduction: Ubiquitous Computing: Anytime, Any-place, Anywhere?, Human-Computer Interaction 13(2): 107-111 (Imielinski and Korth, 1996) Imielinski, T. and Korth, H. F. (1996): Mobile computing, Boston (MA): Kluwer Academic Publishers (Alatalo et al., 2001) Alatalo, T., Heikkinen, T., Kallinen, H. and Pihlajamaa, P. (2001): Mobile information systems, Seminar Thesis, Department of Information Processing Sciences, University of Oulu (Finland) Nomadic computing: (Specht and Oppermann, 1999) Specht, M. and Oppermann, R. (1999): User Modeling and Adaptivity in Nomadic Information Systems, Proc. i3 Annual Conference: Community of the Future, Siena, Italy, October 20 - 22, 1999 Ubiquitous computing: (Weiser, 1991) Weiser, M. (1991): The Computer for the Twenty-First Century, Scient. Ameri-can 265(3): 94-104. http://www. ubiq.com/hypertext/weiser/SciAmDraft3.html (Abowd and Mynatt, 2000) Abowd, G. D. and Mynatt, E. D. (2000): Charting Past, Present, and Future Research in Ubiquitous Computing, ACM Transactions on Computer-Human Interaction 7(1): 29-58 Pervasive computing: (Hansmann et al., 2001) Hansmann, U., Merk, L., Nicklous, M. S. and Stober, T. (2001): Pervasive Com-puting Handbook, Berlin; Heidelberg; New York: Springer-Verlag Everyday computing: (Mynatt, 1999) Mynatt, E. D. (1999): Everyday Com-puting, Whitepaper, Georgia Institute of Technology, Atlanta (GA). www.cc.gatech.edu/fce/ecl/projects/mynatt/EC/ec-white-paper.pdf Invisible computing: (Norman, 1998) Norman, D. A. (1998): The Invisible Computer, Cambridge, MA: MIT Press Embedded computing: (Want et al., 2002) Want, R., Pering, T., Borriello, G. and Farkas, K. I. (2002): Disappearing Hardware, pervasive computing(January - March): 36-47

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PDA, called Newton. Sculley had a vision of PDAs as ubiquitous tools. Newton, however, has not been commercially successful. In 1996 Palm Inc. shipped its first Palm Pilot running under Palm OS. Today, due to an enormous market shift, the Microsoft PocketPC OS (formerly WinCE) powered devices might give these devices its name: PocketPC.

The strength of PDA is within the field of Personal Information Management (PIM), whereas Smartphones put a stronger em-phasis on the communication functions. State of the art PDAs have 5” displays with 240x320 Pixel and 65000 colours. Most PDAs syn-chronise information with a stationary computer over a serial connection, e.g. USB. Other connection means are infrared, Blue-tooth or Wireless LAN (WLAN). Infrared or Bluetooth are primarily intended for the communication between devices (e.g. PDA to Printer; Mobile Phone to Headset; Digital Camera to PDA; etc.) and for the coupling with a mobile phone’s modem providing a connection to the Internet. Wireless LAN (WLAN) works after a similar principle as mobile radio. The reached bandwidths are between 22 and 40 Mbit/s. The coverage, however, is only partial and additional hardware is required. With such a WLAN card the PDA can directly connect to an access point and hence to the Inter-net. The functionality of PDAs is extendable by plugging external hardware into card slots. Common cards are Secure Digital (SD) and Compact Flash (CF). These cards could simply be memory extensions, but smarter cards host hardware such as GPS, digital cameras, connectivity, etc. The two most used operating systems are Palm OS from Palm Computing and Microsoft’s PocketPC 2002. Apart from portable devices like PDAs other kinds of mobile devices exist which are mounted on mobile or moving objects. Such devices are for instance car, ship, and aircraft navigation sys-tems. However, for this work the considered devices will be portable, personal devices.

Important technical improvements for PDAs promise the devel-opments of new display techniques like Organic Light Emitting Diodes (OLED) or electronic paper (Blankenbach 1999; Myers 2002). In addition, initiatives like the Open Systems Graphics (OpenSG) provide fast, real-time capable and portable display systems for virtual and augmented reality systems. These devel-opments will also favour the displays for PDAs. Although there will be improvements in display technologies, physical and eco-nomical limits are in the way of significant advances over the next years. The major problem of mobile devices - and limiting factor

(Blankenbach, 1999) Blankenbach, K. (1999): Multimedia-Displays - von der Physik zur Technik, Physikalische Blätter 55(5): 33-38

(Myers, 2002) Myers, R. L. (2002): Display Interfaces - Fundamentals and Standards, Chichester (NY): John Wiley & Sons

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for all other parts – is battery power. The further development of fuel cells could improve the life time of mobile batteries substan-tially. Mobile networks

Mobile radio networks are composed of several cells (cellular net-work). In each cell a base transceiver station (BTS) is situated. These BTSs are basically antennas sending and receiving radio sig-nals in well defined frequency bands. Furthermore each cell has a unique cell global identity (CGI). To date the implemented stan-dard in Europe is GSM, which was designed for voice communi-cation. Data transfer is possible with a data rate of 9.6 kbit/s. Since this data rate is much too small for bigger data transfers, new third generation (3G) networks will be established in the near future. One example of a 3G network is the new standard Universal Mobile Telecommunications System (UMTS). UMTS is designed for the mobile Internet with theoretical data rates up to 2 Mbit/s. It is circuit switched and packet switched, this means the device is always-on (Siemens 2000). Until UMTS will be fully operational two other technologies with higher data transfer rates are intro-duced: High Speed Circuit Switched Data (HSCSD) and General Packet Radio Service (GPRS). What UMTS and GPRS have in common is that the user pays per data transferred to and from the device instead of connection time. Positioning technologies

For positioning of mobile devices two major approaches can be distinguished (Swedberg 1999; Hein et al. 2000; Mountain and Raper 2000). Network-based positioning works on the basis of cellular mobile networks. The easiest but most inaccurate way to determine the position is using the cell global identity, an inherent structure of a mobile radio network. Using signal run time from device to BTS or vice versa the position can be calculated more accurately with different methods. The second approach is called device-based positioning. In this case the device has any kind of sensor integrated which allows for location determination. In most cases this would be a GPS sensor. A hybrid approach is the combi-nation of both approaches. An example is assisted GPS (A-GPS). In this case even very small fragments of GPS signals can be used, since ephemerid and almanac data is sent over the mobile network to the devices. For many applications, though the orientation is as important as the position itself. Kinematic GPS provides directions, but often an orientation is also needed at stops. Using electronic compasses is tempting, yet it must be doubted if they will be built

(Siemens, 2000) Siemens (2000): UMTS Whitepaper, Siemens AG http://www.siemens.ie/mobile/umts/UMTS%20Whitepaper.pdf

(Swedberg, 1999) Swedberg, G. (1999): Ericsson's mobile location solution, Ericsson Review(4): 214-221

(Hein et al., 2000) Hein, G. W., Eissfeller, B., Oehler, V. and Winkel, J. Ó. (2000): Synergies Between Satellite Navigation and Loca-tion Services of Terrestrial Mobile Communication, Proceedings ION GPS 2000, Salt Lake City (UT)

(Mountain and Raper, 2000) Mountain, D. and Raper, J. (2000): Designing geolocation services for next generation mobile phones systems, Proceedings AGI GIS2000, London

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in general purpose PDAs. In addition, a compass would count for another energy consuming element. A discussion of location sys-tems in general can be found in (Hightower and Borriello 2001) and a good overview of positioning technologies and their use for LBS is given by Wunderlich (2001).

The positioning accuracies show a significant range depending on the method and the area (e.g. city vs. countryside). However, there will always be an error in the position caused by the meas-urement. An example of handling such imprecision is given by Duckham (2003). One must also always consider the purpose of the location information. For certain tasks, rather imprecise posi-tions will do, for others more precise information is essential. Moreover, the further processing and usage of the positions have to be taken into account. There is no sense in measuring positions up to the millimetre, if they are later displayed on a generalised smaller scale map.

Further improvements in positioning technologies can be expected in the next few years. The launch of the European GNNS Galileo, which is interoperable to the GPS, is expected in 2008. This will increase the total number of navigation satellites in the orbit and thus enhance the chances for satellite visibility also in dense urban areas. Galileo will also improve indoor positioning that is so far handled by passive systems, for example infrared sensors. 2.2.2 Web Services, Geoservices, and Location Based Service

Web services seem to be one of the new buzzwords in information technology. The basic concept of web services is a distributed set of software with limited functionality and standard interfaces allow-ing the inter-communication of different web services (Cerami 2002). SUN (2001b) characterizes web services as “accessible over the Web, providing an interface that can be called from another program, being registered by a Web service registry, communi-cating using messages over standard web protocols, and sup-porting loosely coupled connection between systems.” SUN goes even a step further and proclaims smart web services being aware of the user’s identity and used role, preferences and so on. An interesting concept addressed by SUN is the one of shared context. The underlying idea is that services on a low level can be assem-bled to get composite, higher level services providing value-added solutions to users. Furthermore, services can communicate with users, with applications or other web services. If services have to work together, they will need to know about the user’s context in

Duckham et al., 2003) Duckham, M., Kulik, L. and Worboys, M. (2003): Imprecise Navigation, GeoInformatica 7(2): 79-94

(Hightower and Borriello, 2001) Hightower, J. and Borriello, G. (2001): Location Systems for Ubiquitous Com-puting, IEEE Computer(August): 57-66

(Wunderlich, 2001) Wunderlich, T. (2001): Ortsbezogene Information - jederzeit und überall!, ZfV(3): 117-122

(Cerami, 2002) Cerami, E. (2002): Web Services Essen-tials, Sebastopol (CA): O'Reilly & Associates

(SUN, 2001b) SUN (2001b): Open Net Environment (ONE): An Open Architecture for Inter-operable, Smart Web Services, White Paper

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order to provide satisfactory answers. At this point the concept of shared context fits in.

The infrastructure for smart web services proposed by SUN is called Open Net Environment (ONE), strengthening the important issue of open standards. Microsoft follows a similar, though rather proprietary way, called .NET. Anyhow, many standards and tech-nologies are involved, the most important one being XML as a basic language for describing services (see Fig. 14). A service pro-vider should describe the capabilities of the service and its interface with Web Service Description Language (WSDL). To register and later to discover services Universal Description, Discovery, and Integration (UDDI) is used. To encode messages for communication between the services the Simple Object Access Protocol (SOAP) is used. Web services are mostly transported over HTTP.

Web services can be differentiated according to their level of functionality. There are basic or low-level services that offer simple functions and complex or high-level services that combine several functions within one service. One way to achieve more complex and enhanced functionality is the bundling of basic services. The web service architecture provides a mechanism called service chaining. The chaining of services means that the response of one service acts as an input for another or other services. Such an approach offers great flexibility to combine several distributed services in a way as if it were one powerful service. The prerequi-sites for service chaining are a description of the service, well defined interfaces, and syntactic and semantic interoperability.

Fig. 14: Web service model (McLaughlin 2001) (McLaughlin, 2001)

McLaughlin, B. (2001): Java and XML, Sebastopol (CA): O'Reilly & Associates

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Geoservices

The most general notion of geoservices are services that give pre-cise answers to specific spatial questions. However, for this work geoservices are understood as web services that provide, manipu-late, analyse, communicate, and visualise any kind of geographic information (Meng and Reichenbacher 2003). There are several types of geoservices, not all aimed at mobile users.

In recent years several standardisation processes have proceeded to specify specifications to guarantee interoperability of geographic information and geoprocessing. The two major organisations in-volved in these processes are the International Standardisation Organisation (ISO) and the Open GIS Consortium (OGC). At ISO the ISO/TC 211 is concerned with standardising Geographic Information/Geomatics. These ISO specifications are currently harmonised with the Open GIS service architecture. In ISO 19119 a general service framework is specified and a service is defined as “a distinct part of the functionality that is provided by an entity through interfaces”. ISO 19101 provides a classification of geo-graphic services with the Extended Open Systems Environment (EOSE) model for geographic information. This model distin-guishes six classes of geographic services. Table 3 shows the six classes and example services relevant for this work as well as the corresponding ISO and/or OGC specifications. The model also provides a method for organising services that are meaningful for a specific situation. These so called service organisation folders (SOF) are references to services, either individual services or ser-vice chains that are also specified in the framework. SOF could be a means to map relevant services to specific usage contexts. Geographic human interaction services

Catalogue-centric service that views and browses meta-data about services Spatial-centric service for editing, displaying, querying, and analyzing map data Calculation-centric service allowing viewing and manipu-lation of geographic data using a spreadsheet format Chain definition editor Geographic symbol editor (ISO 19117 - Portrayal) Feature Generalization editor

Geographic model/ information management services

Feature access service (OGC Simple Feature Access, Web Feature Service; ISO 19125-1 – Simple feature access – Part1: Common architecture) Map access service (OGC Web Map Service; ISO 19128 – Web Map server interface; ISO 19117 - Portrayal) Coverage access service (OGC Coverages; ISO 19123 – Schema for coverage geometry and functions) Gazetteer Service (OGC Gazetteer Service, OGC Geoparser Service, OGC Geocoder Service; ISO 19112 - Geographic referencing by geographic identifiers)

(Meng and Reichenbacher, 2003) Meng, L. and Reichenbacher, T. (2003): Geodienste für Location Based Services, Proceedings 8. Münchner Fort-bildungsseminar Geoinformationssysteme, TU München, March 12-14, 2003

Standards

ISO 19119: www.opengis.org/docs/02-112.pdf

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Geographic metadata catalogue – with discovery, access and management subservices (OGC Web Catalog Ser-vice; ISO 19115 - Metadata )

Geographic work-flow/ task man-agement services

Chain definition service Subscription service

Geographic processing services Spatial Thematic Temporal Metadata

Coordinate conversion service Subsetting service Feature matching service Feature generalization service Route determination service Positioning service (ISO 19116 – Positioning services Proximity analysis service Feature generalization service Spatial Counting service Geoparsing service Geocoding service Subsetting service Temporal proximity analysis service Geographic annotation service

Geographic communication services

Encoding service (ISO 19118 - Encoding) Transfer service (ISO 19118 - Encoding) Geographic compression service Geographic format conversion service

Geographic sys-tem management services

Table 3: ISO Geographic services

The OGC has proposed a framework for geoservices, named Open Web Services (OWS) that fits well in the geoservice model mentioned before. The OGC Open Location Services (OpenLS) specification defines Core Services and Abstract Data Types (ADT). In addition it defines the requirements of a GeoMobility Server (GMS), an open location service offering the core services (OGC 2003, p. 19). A GeoMobility server is a component that offers some basic functionality on which location-based applications can be built. This functionality is comprised by the OpenLS Core Ser-vices (Fig. 15): Route, Location Utility, Directory, Presentation, and Gateway. A GMS uses open interfaces to access network location capacity and offers access to its OpenLS Core Services through interfaces. The GMS preferably provides content such as maps, routes, addresses, POIs, traffic, etc. stored according to the OpenLS Information Model, consisting of ADTs. A GMS can also access other content sources via the Internet.

(OGC, 2003) OGC (2003): OpenGIS Location Ser-vices (OpenLS): Core Services, OGC Implementation Specification, OGC 03-006r1, Open GIS Consortium

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Web MapService (WMS)

Web FeatureService (WFS)

gateway service

directory service

route service

OpenLS Core Services

presentation service

geocoder service

reverse geocoder servicepositioningservice

directories

geodatabase

route data

Address ADT POI ADT

AOI ADT

Position ADT

Location ADT

Position ADT

Address ADT

Route Geometry ADTRoute Summary ADT

gazeteer servicegeoparser service

Fig. 15: OpenLS Framework (after OGC 2003)

The OpenLS framework defines a presentation (map portrayal) service as “a network-accessible service that portrays a map made up of a base map derived from any geospatial data and a set of ADT’s as overlays” (OGC 2003, p. 4). The OpenLS platform also offers a standard way for encoding request and response messages as well as ADT’s with XML, the XML for Location Services (XLS). Location Based Services

One category of geoservices for mobile users are location based services (LBS). LBSs are services accessible with mobile devices through the mobile network and utilizing the ability to make use of the location of the terminals. LBS provide specific, relevant information based on the current location to the user. In (OGC 2003, p. 4) LBS is defined as ”a wireless-IP service that uses geo-graphic information to serve a mobile user [or] any application service that exploits the position of a mobile terminal.” Another definition, emphasizing the importance of the information, is given by Ovum (2000, p. 5): “[LBS are] network-based services that inte-grate a derived estimate of a mobile device’s location or position with other information so as to provide added value to the user.” The telecommunication industry has just started to offer LBS to subscribed users. The idea is that a user books such a service and will get information from the network provider which is relevant to his/her current position. For a basic introduction to LBS see for example (Gasenzer 2001; Koeppel 2000; SUN 2001a). The impor-

(OGC, 2003) OGC (2003): OpenGIS Location Ser-vices (OpenLS): Core Services, OGC Implementation Specification, OGC 03-006r1, Open GIS Consortium

(Ovum, 2000) Ovum (2000): Mobile Location Services: Market Strategies, Ovum Ltd.

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tance of GIS functions for LBS is discussed in (Virrantaus et al. 2001).

The core services of LBS rely on fundamental GIS functions that are also contained in the OpenLS framework (see Fig. 15). The fol-lowing list describes the services by the LBS company pocket-it:

• Positioning: provides the location of the mobile user by connecting to the network operatorʹs positioning system

• Geographic search: searches for any geographic feature • Geocoding service: determines X and Y coordinates for

relevant POIs or addresses • Reverse Geocoding: converts coordinates into a geographic

text format • Proximity search: find nearest POI or POIs nearby from a

position or address, e.g. the nearest bus stop, ATM, drug-store, post office etc.

• Routing service: calculates the shortest or fastest route between two points or a number of points (current position, address, POI) and direction instructions (street names, distances, and turns).

• Mapping service: High quality map display of POI based on a request for a specific location with pan and zoom functionality and optimised for the requesting device

Especially in the case of LBS two different ways of information dissemination are push and pull services. In a pull service the information is desired and expected by the user; the user actively pulls the information. The download and browsing of web pages is an example for a pull service. In a push service the information is pushed to the user without a user request. An example would be an advert of a special offer when passing a shop. Geovisualisation services

This category of geoservices provides any kind of visualisation of geographic information. For mobile cartography, geovisualisation services are of the utmost interest. A more detailed discussion of geovisualisation services is given in (Meng and Reichenbacher 2003). Geovisualisation service is also called portrayal (ISO 19117) or presentation service (OGC). A service-oriented understanding of geovisualisation differs in many regards from traditional map products. The trend to more flexible, on-demand delivery of geo-visualisation initiated through web mapping will continue even stronger in the mobile Internet. Table 4 gives a rough, yet incom-plete overview of the main differences.

(Gasenzer, 2001) Gasenzer, R. (2001): Mobile Commerce und Location Based Services: Positions-basierte Leistungsangebote für den mobilen Handel, HMD - Praxis der Wirtschaftsinformatik(8): 37-51

(Koeppel, 2000) Koeppel, I. (2000): What are Location Services? - From a GIS Perspective, Sun Microsystems. 2001. http://www.jlocationservices.com/company/esri/What%20are%20Location%20Services.html

(SUN, 2001a) SUN (2001a): Java Location Services: The new Standard for Location-Enabled E-Business, White Paper. http://www.jlocationservices.com/company/Sun/JavaLocServBR_R4.pdf

(Virrantaus et al., 2001) Virrantaus, K., Veijalainen, J., Markkula, J., Katanosov, A., Garmash, A., Tirri, H. and Terziyan, V. (2001): Developing GIS-Supported Location-Based Services, Proceedings WGIS 2001, Kyoto, Japan

LBS functionality: www.pocket-it.com

(Meng and Reichenbacher, 2003) Meng, L. and Reichenbacher, T. (2003): Geodienste für Location Based Services, Proceedings 8. Münchner Fort-bildungsseminar Geoinformationssysteme, TU München, March 12-14, 2003

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map products geovisualisation services information detail more detailed less detail information content comprehensive focussed, more relevant personalisation one size fits all can be adapted usage more enduring short-term, instant design and production by cartographers automatically, based on carto-

graphic methods graphic quality high inferior, but enhanced quality in use link to other informa-tion

more difficult, poor interoperability

built-in (service chaining), better interoperability

functionality greater functionality limited functionality

Table 4: Comparison of map products and geovisualisation services

The services described so far can be ordered in a hierarchy. Although a geoservice must not necessarily be distributed and web-based, geoservices normally are a subset of web services. A geoservice is the most general category of service related to geo-graphic information. LBSs and geovisualisation services are subsets or implementations of a geoservice. Both, LBSs and geo-visualisation services, can be based on lower level services such as web feature services or web map services. Furthermore, they can also incorporate one another, i.e. there are LBS with a geovisuali-sation component and geovisualisation services based on LBS functionality. Open standards for geoservices

As a technology web mapping has matured over the last couple of years. Due to its universality the Internet, and hence web mapping as well, demands for a high degree of interoperability. The Open GIS Consortium has established standards in many realms of GI. For web mapping the OGC has defined a standard, the specifi-cation for Web Map Servers (WMS). Together with the Web Feature Server (WFS) specification and other specifications it offers an open standard for web mapping. Other standardisation efforts have brought up XML based formats for modelling geographic data, the Geography Markup Language (GML), and presenting geographic data as vectors, the Scalable Vector Graphics (SVG). SVG is a multi purpose graphic format, but as Neumann and Winter (2000) confirm well suited for cartographic purposes. Most recent activities establish a specification of SVG for mobile needs

In academia the need for an open and interoperable platform has also been recognised. Edwardes et al. (2003a) describe the require-ments of an open research platform for on-demand mapping and generalisation.

(Neumann and Winter, 2000) Neumann, A. and Winter, A. (2000): Kartographie im Internet auf Vektorbasis, mit Hilfe von SVG. http://www.carto.net/papers/svg/index_d.html

(Edwardes et al., 2003a) Edwardes, A., Burghardt, D., Bobzien, M., Harrie, L., Reichenbacher, T., Sester, M. and Weibel, R. (2003a): Map Generalisation Technology: Addressing the Need for a Common Research Platform, Proceedings 21st International Cartographic Conference, Durban, South Africa, August 10-16, 2003

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Chapter 3

3 Approaches for visualisation of geographic information on mobile devices

If you have been far, there is always someone who’s been further than your far, at last you’re straight and you make a new start – The Beautiful South: ‘Hooligans don’t fall in love’.

3.1 Related work

Only little work has been done on how to visualise geographic information, especially map data, on very small displays. It is sur-prising that even for screen display in general hardly any studies have been conducted. Exceptions are a few studies of the issues and problems in screen design for cartographic visualisation and proposals of new minimal dimensions; see for example (Spiess 1994; Malic 1998; Wilfert 1998; Arleth 1999; Thissen 2000; Brunner 2000; Brunner 2001; Neudeck 2001). Moving on to even smaller displays, used in PDA for instance, these problems intensify. Reading map graphics becomes very difficult. Important map functions, e.g. providing spatial context and overview, are very hard to keep on small displays. Brunner (2001) describes different effects resulting from the raster technology of screens. Several graphical primitives (e.g. circles) that are widely used for map symbols and map fonts are highly sensitive for graphical distor-tions.

Some research has been done on using graphics on small dis-plays. But maps are often more complex than simple graphics. Moreover, the smaller the displays are, the more important graphi-cal issues like minimal dimensions become. Neudeck (2001) studied different proposals of minimal dimensions for screen maps and offers a new set of threshold values based on tests. These minimal dimensions have to be much larger to ensure legibility on

(Spiess, 1994) Spiess, E. (1994): Some Problems with the Use of Electronic Atlases, LIBER Quarterly. http://www.konbib.nl/ infolev/liber/articles/1spiess.htm

(Malic, 1998) Malic, B. (1998): Physiologische und technische Aspekte kartographischer Bildschirmvisualisierung, Dissertation, Inst. für Kartographie und Topographie, Universität Bonn

(Wilfert, 1998) Wilfert, I. (1998): Internet und Kartogra-phie, in M. Buchroithner, W. G. Koch and I. Wilfert (Eds.), Kartographische Bausteine, Band 14, Dresden: Techni-sche Universität Dresden, Institut für Kartographie.

(Arleth, 1999) Arleth, M. (1999): Problems in screen map design, Proc. 19th International Cartographic Conference (ICA 1999), Ottawa, August 14-21, 1999

(Thissen, 2000) Thissen, F. (2000): Screen-Design-Handbuch: Effektiv informieren und kommunizieren mit Multimedia, Berlin; Heidelberg: Springer-Verlag

(Brunner, 2000) Brunner, K. (2000): Limitierungen bei der elektronischen Bildschirmanzeige von Karten, in B. Schmidt and C. Uhlenküken (Eds.), Visualisierung raumbezogener Daten: Methoden und Anwendungen, Bd. II: Beiträge zum 3. GeoViSC-Work-shopMünster: Institut für Geoinformatik, Westfälishe Wilhelms-Universität Münster


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small screens. Neudeck also presents first practical guidelines for screen map graphics that can be embedded in the design of mobile maps. 3.1.1 Research approaches

Most of the research related to this work is in the field of context-aware mobile computing or geographic information services for tourists.

One of the earliest context-aware systems has been developed at Xerox PARC in Palo Alto among others by the pioneer of ubiqui-tous computing Mark Weiser. ParcTab is a prototype demonstrating applications like information access, communi-cation, computer supported cooperative work (CSCW), remote control and local data processing in office environments (Want et al. 1995). The device positioning is based on infrared technology and can display different information dependent on its position.

In the mid 1990ies at Georgia Institute of Technology the Cyber-guide Project was initiated (Long et al. 1996). It is a series of prototypes of portable tour guides. They are all based on the Apple message pad (Newton). Indoor positioning is done by infrared technology, outdoor positioning applies GPS. Cyberguide is built on three modules: a map module, a communication module, and a positioning module. The maps are displayed as bitmaps. Infor-mation which is sent to the message pads is centrally stored on a stand-alone computer. Dynamic changes of information are not easy to propagate. Another drawback is the fact that an increase in the information amount could crack the capacity of a stand-alone system.

At Rutgers University the research project DATAMAN was con-ducted (Acharya et al. 1994). The goal was to enable data handling in a mobile environment. DATAMAN is map centred, i.e. the user interface is based on a map.

From mid 1997 to mid 1999 the Distributed Multimedia Research Group of Lancaster University and Lancaster City Council con-ducted a joint research project named GUIDE (Cheverst et al. 2000). The group established a prototype of a context-sensitive, mobile multimedia, computer supported tool for visitors of Lancaster. While walking around the town, visitors can constantly view information about sightseeing objects displayed on a mobile device.

(Want et al., 1995) Want, R., Schilit, B., Adams, A., Gold, R., Petersen, K., Goldberg, D., Ellis, J. and Weiser, M. (1995): The ParcTab Ubiquitous Computing Experiment, Technical Report CSL-95-1, Xerox Palo Alto Research Center, Palo Alto (CA)

(Long et al., 1996) Long, S., Aust, D., Abowd, G. and Atkenson, C. (1996): Cyberguide: Prototyping Context-Aware Mobile Applications, Proceedings ACM CHI 96 Conference on Human Factors in Com-puting Systems. http://www.acm.org/sigchi/chi96/proceedings/shortpap/Abowd/gda1txt.htm

(Brunner, 2001) Brunner, K. (2001): Kartengestaltung für elektronische Bildanzeigen, in, Karto-graphische Bausteine, Band 19, Dresden: Technische Universität Dresden, Institut für Kartographie

(Neudeck, 2001) Neudeck, S.: Zur Gestaltung topograf-ischer Karten für die Bildschirmvisualisierung. Disserta-tion, Inst. für Photogrammetrie und Kartogra-phie. Studiengang Geodäsie und Geoinforma-tion, Univ. der Bundeswehr München, 2001

(Acharya et al., 1994) Acharya, A., Imielinski, T. and Badrinath, B. R. (1994): DATAMAN Project: Towards a Mosaic-like Location Dependant Information Service for Mobile Clients, TR-320, Rutgers University. ftp://www.cs.rutgers.edu/ pub/technical-reports/dcs-tr-320.ps.Z

(Cheverst et al., 2000) Cheverst, K., Davies, N., Mitchell, K., Friday, A. and Efstratiou, C. (2000): Developing a Context-aware Electronic Tourist Guide: Some Issues and Experi-ences, Proceedings CHI 2000, The Hague, Netherlands, April 2000. http://www.guide.lancs.ac.uk/CHIpaper.pdf


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Another early research project linked to LBS was Hyper-Interaction within Physical Space (HIPS). The objective of this EU project was to develop a service for museum visitors that allowed them to access attribute information connected to physical objects in real-time. HIPS predominantly dealt with the adaptation of hypermedia with respect to interactive tour guides (Broadbent and Marti 1997).

Several feasibility studies have been carried out in the OnTheMove project (Kreller et al. 1998) initiated by Ericsson Euro-lab to demonstrate the potential of 3G telecommunication systems – UMTS – for mobile broadband multimedia applications. The mobile-aware city guide application aimed at building prototypes on the basis of the Mobile Application Support Environment for 3G systems (MASE). Two prototypes, a Java applet and a Java stand-alone application, have been developed. The location manager module of the prototypes is based on GPS. Map data is displayed as scanned raster city maps offering panning func-tionality. The user can also display his/her position and select and deselect single layers.

The Fraunhofer Computer Graphics Center in Rostock ran the Mobile Visualisation (MoVI) project (Kirste et al. 1995). The pro-ject is based on the concept of Mobile Data Terminals (MDT). Some new ideas concerning level of detail and detail of demand are very interesting. Although only raster data is considered, new tech-niques for displaying map data on small displays are presented. In another project several Institutes of Fraunhofer Gesellschaft inves-tigate mobile user support. The SAiMotion project aims at providing adaptive and situation-aware solutions for nomadic users (Heidmann and Hermann 2003, p. 126).

Strongly connected with the basic idea, but with a commercial background is the MOGID (Mobile Geo-depended Information on Demand) project (Balsiger et al. 2000). The location technology used is an enhanced UL-TOA (uplink time of arrival), which is software based and therefore applicable to almost any mobile device. The solution is implemented as a Java applet that can be accessed via AT commands from the GSM module. The informa-tion is stored in a standard relational DBMS. Since it is a commercial service, only information which is interesting enough according to the provider and worthy in the sense that people might pay for will be stored in the locational database.

(Broadbent and Marti, 1997) Broadbent, J. and Marti, P. (1997): Location aware mobile interactive guides: usability issues, Proceedings The Fourth International Conference on Hypermedia and Interactivity in Museums (ICHIM '97), Paris, September 1-5, 1997. http://www.ing.unisi.it/lab_tel/ hips/hips_pub.htm

(Kreller et al., 1998) Kreller, B., Carrega, D., Shankar, J. P., Salmon, P., Böttger, S. and Kassing, T. (1998): A Mobile-Aware City Guide Application, Proceedings ACTS Mobile Summit 1998, Rhodos, Greece

(Kirste et al., 1995) Kirste, T., Heuer, A., Kehrer, B., Schumann, H. and Urban, B. (1995): Concepts for Mobile Information Visuali-zation - The MoVi-Project, Proceedings Sixth Eurographics Workshop on Visuali-zation in Scientific Computing, Chia, Italy, May 3-5, 1995

(Heidmann and Hermann, 2003) Heidmann, F. and Hermann, F. (2003a): Visualisierung raumbezogener Informationen für ultraportable mobile Systeme, in, Visualisierung und Erschließung von Geodaten - Seminar GEOVIS 2003, 26. bis 27. Februar 2003, Universität Hannover, Karto-graphische Schriften, Band 7, Bonn: Kirschbaum Verlag, 121-131

(Balsiger et al., 2000) Balsiger, P., Sun, D., Gomez, M., Pellandini, F., Aeschlimann, M., Dworzak, C., Hubmann, M. and Sollberger, A. (2000): MOGID: Mobile Geo-depended Information on Demand, Proceedings Workshop on Position Dependent Information Services - Joint W3C-WAP Forum Workshop, Sophia Antipolis, Nice, February 2-3, 2000. http://www.w3.org/Mobile/posdep/wap-v2.htm


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In the project Deep Map an interdisciplinary research group at the European Media Lab (EML) developed a prototype of a digital personal mobile tourist guide for the city of Heidelberg (Malakka 2000). Deep Map integrates research from various areas of com-puter science, such as geo-information systems, data bases, natural language processing, intelligent user interfaces and knowledge representation. The goal of the project was to develop information technologies that can handle huge heterogeneous data collections, complex functionality and a variety of technologies, but are still accessible for untrained users. The core of the guide is a GIS. How-ever, the GIS will be extended to the fourth dimension by integrating temporal information (e.g. city history). Tour planning, virtual tours, and localisation of users per GPS are interfaces to this project. There is also the interesting sub-project Talking Map that investigates speech recognition, natural language input/output interfaces, verbal directions, and spatial reasoning. Especially the speech output could be of interest as an alternative means to deliver spatial data to the user.

The follow-up project CRUMPET aimed at designing usable mobile services for tourists and investigated service adaptation techniques (Poslad et al. 2001).

NEXUS is a project dealing with a platform for mobile services (Volz et al. 2002). The basic concept is based on Virtual Infor-mation Towers that hold information about the area they service. The main focus is on modelling geographic information ade-quately for mobile service provision and offering an open platform for other service providers to build their location services on top of it.

Different projects propose solutions for displaying geographic information on small displays. The LoL@ project developed a prototype tourist guide for 3G networks and handsets (Gartner and Uhlirz 2001). The goal of the project was to build a demon-strator for an UMTS based map service for the city of Vienna. The map graphics has been optimised for the display size of a Smart-phone. The map has a slight skew that, together with the silhouette of important sightseeing spots, gives a more perspective spatial impression (Fig. 16, left).

(Malakka, 2000) Malakka, R. (2000): Deep Map: The Multilingual Tourist Guide. http://www.eml.villa-bosch.de/english/research/ deepmap/deepmap.html

(Poslad et al., 2001) Poslad, S., Laamanen, H., Malaka, R., Nick, A., Phil, B. and Zipf, A. (2001): CRUMPET: Creation of User-friendly Mobile Services Personalised for Tour-ism, Proceedings 3G 2001, London, March, 26-28 2001

(Volz et al., 2002) Volz, S., Haala, N. and Klinec, D. (2002): NEXUS - An Open Global Infrastructure For Spatially Aware Appli-cations, Geoinformatics(July/August): 24-26.

(Gartner and Uhlirz, 2001) Gartner, G. and Uhlirz, S. (2001): Cartographic Concepts for Realizing a Location Based UMTS Service: Vienna City Guide "Lol@", Proceedings 20th International Cartographic Conference, Beijing, China, August 6 - 10, 2001


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Fig. 16: LoL@ prototype (Gartner and Uhlirz, 2001) and GiMoDig design proposal for navigation map (Nissen et al., 2003)

A few EU projects deal or dealt with mobile geographic informa-tion visualisation: A similar goal as in the CRUMPET project was pursued in the HYPERGEO project (Mountain and Raper 2000). In the VATGI project standards for the exchange of thematic geo-graphic information (e.g. POI) have been developed (VATGI-Consortium 2001). Two recent EU projects are very closely related to this research.

GiMoDig (Geospatial info-mobility service by real-time data-inte-gration and generalisation) is a project of several National Map-ping Agencies aiming at developing spatial data delivery from national primary geo-databases for mobile use and the necessary real-time data integration and generalisation methods. In a work package on small-display cartography, possible map designs are examined and guidelines elaborated (Nissen et al. 2003). Fig. 16 (right) shows a prototype of a navigation map for a Smartphone.

The goal of the WebPark project is to develop personalised value-added LBSs for mobile users in national parks (Krug et al. 2003). National parks in coastal and alpine areas are used as test fields. First approaches for visualising species information for visitors of the Swiss national park are proposed by Edwardes et al. (2003b). This concept foresees an activity based semantic filtering of infor-mation and investigates the architecture of a generalisation service.

An approach similar to this research is taken by Urquhart et al. (2003). The goal is to ensure the usability of LBS by developing appropriate representations for mobile devices by applying a user-centred approach to LBS development and the design of optimised cartographic representations for mobile contexts.

This research work also shares some substantial ideas of the approach of ‘situational visualizations’, although situational visualisations have a lot in common with virtual environments and augmented reality and are more focussed on exploring the envi-ronment. Situational visualisations are based on a mobile ‘Virtual

(Mountain and Raper, 2000) Mountain, D. and Raper, J. (2000): Designing geolocation services for next generation mobile phones systems, Proceedings AGI GIS2000, London

(VATGI-Consortium, 2001) VATGI-Consortium (2001): VATGI Project INFO 2000 - PUB 1199 VATGI FINAL REPORT, Public Report, VATGI Consortium. http://www.VATGI.org

GiMoDig

Project Homepage: gimodig.fgi.fi/index.php

(Nissen et al., 2003) Nissen, F., Hvas, A., Münster-Swendsen, J. and Brodersen, L. (2003): Small - Display Cartography, GiMoDig D3.1.1 (Public Deliverable), KMS: National Survey and Cadastre - Denmark. http:// gimodig.fgi.fi/pub_deliverables/D3_1_1.pdf (Krug et al., 2003) Krug, K., Mountain, D. and Phan, D. (2003): WebPark: Location-Based Services for mobile users in protected areas, Geoinformatics(March). http://www.soi.city.ac.uk /~dmm/research/pubs/WParticle_by_Consortium_GeoInformatics_nr2_March_2003.pdf (Edwardes et al., 2003b) Edwardes, A., Burghardt, D. and Weibel, R. (2003b): WebPark - Location Based Services for Species Search in Recreation Area, Proceedings 21st Int.l Cartographic Conference, Durban, South Africa, August 10-16, 2003 (Urquahrt et al. 2003) Urquhart, K., Cartwright, W., Miller, S., Mitchell, K., Quirion, C. and Benda, P. (2003): Ensuring Useful Cartographic Representations in Location-Based Services, Proceedings ICC, Durban, South Africa, August 10-16, 2003


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GIS’ that takes the user’s spatio-temporal location, his/her actions and the situatedness in a environment into account (Krum et al. 2001).

Useful research on dynamic maps has been conducted by Arikawa et al. (1994). The concept of dynamic maps includes queries of geodatabases and selection of appropriate visualisation methods. Of interest is the idea to adapt the number of displayable features in the retrieval set according to a map saturation.

Some research has been conducted on adaptive graphics. Krüger et al. (2000) demonstrate the adaptation of perspective graphics for wayfinding tasks in buildings. Jung and McKeown (2001) describe an XML based approach of adapting different kind of graphics, to which they count maps as well. One of their examples deals with quantitative and qualitative changes that can be applied to maps.

Scholz (2002) developed an application closely related to adap-tive maps. In a scenario he describes event based screen maps for pedestrians. The rule-based modelling approach includes the detection of situations and offers reactions reflected in the map, such as the user position update, different scales depending on movement speed (walking or bus), displaying the bus network depending on drives or stops of the bus, etc.

Adaptation of maps sensu strictu has so far been investigated only by (Heidmann 1999; Chalmers et al. 2001; Zipf 2002; Zipf and Richter 2002). Heidmann (1999, p. 253) explicitly speaks of adaptive work graphics that automatically adapts itself to the user charac-teristics and the current task context. He identifies the models needed for adaptive behaviour, the user model, the task model, and the situation model and gives examples of parameters for each model. This work has strong influence on the framework of mobile cartography (chapter 4), especially on the user, activity, and con-text. The research of Chalmers et al. (2001) is targeted at adapting maps for different bandwidths, i.e. reducing the file size by adapting the content of the map. Their approach deduces from an original map an adapted map with reduced content for a transmis-sion on a 10kB/s connection. This approach basically seems to generalise maps by applying a selection operator. Although this can be considered as adaptation, it is not as comprehensive as the approach of Zipf and the one developed in this work.

(Arikawa et al. 1994) Arikawa, M., Kawakita, H. and Kambayashi, Y. (1994): Dynamic Maps as Composite Views of Varied Geo-graphic Database Servers, Proceedings First International Conference on Appli-cations of Databases, ADB-94, Vadstena, Sweden, June 21-23, 1994

(Krum et al. 2001) Krum, D. M., Ribarsky, W., Shaw, C. D., Hodges, L. F. and Faust, N. (2001): Situational Visualization, Proc. ACM Symposium on Virtual Reality Software and Technology, Banff, Canada, November 15-17, 2001, ACM Press

(Krüger et al. 2000) Krüger, A., Baus, J. and Butz, A. (2000): Smart Graphics in Adaptive Way Descriptions for Pedestrians, Proceedings Advanced Visual Interfaces (AVI '00), Palermo, Italy, May 23-26, 2000, ACM Press (Jung and McKeown, 2001) Jung, B. and McKeown, J. (2001): Adaptive Graphics, Proceedings XML2001, Orlando (FL) (Scholz, 2002) Scholz, F. O. (2002): Ereignisgesteuerte Bildschirm-karten, Diplomarbeit, Institut für Informatik - Abteilung III, Rheinische Friedrich-Wilhelms-Universität Bonn

(Heidmann, 1999) Heidmann, F. (1999): Aufgaben- und nutzerorientierte Unterstützung kartogra-phischer Kommunikationsprozesse durch Arbeitsgraphik: Konzeptionen, Modellbil-dung und experimentelle Untersuchun-gen, Herdecke: GCA-Verlag

(Chalmers et al., 2001) Chalmers, D., Sloman, M. and Dulay, N. (2001): Map Adaptation for Users of Mobile Systems, Proceedings WWW10, Hong Kong, May 2001

(Zipf, 2002) Zipf, A. (2002): User-Adaptive Maps for Location-Based Services (LBS) for Tour-ism, in K. Woeber, A. Frew and M. Hitz (Eds.), Proceedings of the 9th Inter-national Conference for Information and Communication Technologies in Tourism, ENTER 2002, Innsbruck, Austria, Springer Computer ScienceBerlin; Heidelberg: Springer-Verlag. http://www.eml.villa-bosch.de/english/ homes/zipf/ENTER2002.pdf

(Zipf and Richter, 2002) Zipf, A. and Richter, K.-F. (2002): Using Focus Maps to Ease Map Reading: Developing Smart Applications for Mobile Devices, Künstliche Intelligenz(4): 35-37


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Zipf (2002) studies the potential of adaptive map services for tourists and offers a first overview of the design steps involved in adaptive map generation. He gives a few examples of possible map adaptations: culture specific map colouring, map generalisa-tion, user oriented-maps, and focus maps. Focus maps are of special interest on small displays (Zipf and Richter 2002). The basic idea is to apply focus-context techniques to map design, i.e. moving the most relevant spatial information in focus and show-ing it with full detail (exaggerating or emphasizing) while dis-playing the other, contextual information with less detail and graphically not that prominently. For this purpose regions of interest have to be modelled. The methods used to emphasize the region of interest are generalisation and colour use. The region of interest is compared to the rest of the map either generalised less or symbolised with brighter colours. The former approach is simi-lar to the variable-scales solution discussed in the next section.

The projects and approaches presented differ in their extent of covering cartographic design issues. With the advent of mobile computing and context sensing technologies, the first projects mainly examined the technical aspects of context-awareness, e.g. ParcTab, CyberGuide, and DATAMAN. In the second half of the 1990ies, more and more projects took up the idea of LBS. Some of them were intended as demonstrators of possibilities of 3G mobile networks (UMTS) such as OnTheMove and Lol@. Interestingly most projects target tourists (e.g. GUIDE, DeepMap, CRUMPET, Lol@) and pedestrian navigation (NAVIO, GiMoDig). A trend to more per-sonalised, user adaptive map based services can be observed from the beginning of this millennium with projects like DeepMap, CRUMPET, GiMoDig, and WebPark. Whereas these projects all have an influence on the research presented here, not all of them pro-vide solutions applicable to the problem area described in chapter 1. The next section will therefore describe the solutions developed that can be used for displaying geographic information on small displays. 3.1.2 Existing solutions

Besides research projects, industry solutions offer a view on the commercial state of the art in mobile geographic information visu-alisation. These solutions are strongly influenced by solutions of car navigation systems. After an overview of city map guides, navigation systems, and LBS, a brief outlook on newer solutions for handling the small screen problem round off the contemplation of related work.

(Zipf, 2002) Zipf, A. (2002): User-Adaptive Maps for Location-Based Services (LBS) for Tour-ism, in K. Woeber, A. Frew and M. Hitz (Eds.), Proceedings of the 9th Interna-tional Conference for Information and Communication Technologies in Tourism, ENTER 2002, Innsbruck, Austria, Springer Computer ScienceBerlin; Heidelberg: Springer-Verlag. http://www.eml.villa-bosch.de/english/ homes/zipf/ENTER2002.pdf



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City map guides

The basic functionality of solutions for mobile geographic infor-mation visualisation is provided by city maps with searchable POIs like the Falk City Guide. These map guides include a GPS positioning and tracking function. The map function is in general also the basic component for all other systems and services. Navigation systems

Long before the success of the PDA small displays were used in car navigation systems. The first systems have been installed in luxury class cars. Today these fixed mounted systems are almost standard in middle class cars. Recently solutions based on PDA have entered the market. The map graphics is simplified and designed for the special purpose of navigating on road networks. Fig. 17 (left) illustrates a perspective route display of TomTom Navigator, a navigation system for PocketPCs. These navigation systems can also be used off-board. Location based services

LBS with visualisation components are increasingly provided by telecommunication companies. These services cover simple city maps, routings, business finder, ATM finder etc. The example in Fig. 17 (right) shows a map related service for PDAs provided by the telecommunication company O2. Different studies have proved that a visual communication of geographic information in the form of maps is high on the users’ wish list of LBS (Kölmel and Wirsing 2002).

Fig. 17: Examples of car navigation system map displays and LBS

Solutions to displaying geospatial information on small displays

One solution to handle the limited map space is to drop the prin-ciple of uniform scale normally used in maps. In the MoVi project fisheye views of city maps were examined (Rauschenbach 2000). The city map has a regular scale in the focus area (generally in the

City map guides

Falk City Guide: www.falk.de

Navigation Systems

TomTom Navigator 2: www.tomtom.com Destinator 3.0: www.destiator.de MobileNavigator: www.navigon.de MobilePilot: www.tele-info.de map&guide travelbook: www.map&guide.de

Location Based Services

Handy-Finder: www.o2-online.de PinPoint:www.o2.co.uk/business/productsservices/locationservices/pinpoint/0,,142,00.html

(Kölmel and Wirsing, 2002) Kölmel, B. and Wirsing, M. (2002): Nutzererwartungen an Location Based Servcies - Ergebnisse einer empirischen Analyse, in A. Zipf and J. Strobl (Eds.), Geoinformation mobil, Heidelberg: Wichmann Hüthig Verlag, 85-97

(Rauschenbach, 2000) Rauschenbach, U. (2000): Bedarfs-gesteuerte Bildübertragung mit Regions of Interest und Levels of Detail für mobile Umgebungen, Dissertation, Fakultät für Ingenieurwissenschaften, Universität Rostock. http://wwwicg. informatik.uni-rostock.de/Projekte/MoVi/ Publications/ dissRauschenbach/diss.pdf


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middle of the map) and is distorted in the other parts of the map, represented at smaller scales.

A similar approach is taken in the GiMoDig project. The use of variable-scales allows for a better exploitation of the limited resource ‘map space’. Harrie et al. (2002) demonstrate a procedure for generating variable-scale maps with SVG. Fig. 18 (left) shows an example of a variable-scale map developed in the GiMoDig project.

Fig. 18: Variable-scale map for small displays (Harrie et al., 2002) and radial generalisation in variable-scale maps (Rappo, 2003)

The variable-scale approach can help to solve the problem of lacking map space, i.e. a larger geographic area can be displayed on the same display area. However, it does not necessarily make the map more legible. The map graphics is still cluttered towards the edge of the display. For that reason a new kind of generalisa-tion, radial generalisation, is required. Radial generalisation will radially simplify the map from the centre, i.e. the focus of the map and the user’s position, towards the edges. Such an approach has been taken in the work of Rappo (2003). Fig. 18 (right) illustrates the decreasing level of detail towards the edges of the map display.

The schematisation of topology is a solution for maps showing primarily topological information, for instance traffic network maps (e.g. Barkowsky et al. 2000; Avelar 2002). The result of such a graph schematisation is shown in the schematic map in Fig. 19 (left). Schematic maps are “obtained by relaxing spatial and other constraints from more detailed maps … [and] are seen as concep-tual representations of the environment” (Casakin et al. 2000). Sometimes these kinds of maps are also called topograms. Fig. 19 (right) depicts an example of such a topogram (Brunner 2001). The simple graphics is well suited for small displays, but this sort of

(Harrie et al., 2002) Harrie, L., Sarjakoski, L. T. and Lehto, L. (2002): A variable-scale map for small-display cartography, Proceedings ISPRS Symposium on geospatial theory, proc-essing, and applications, Ottawa, Canada

(Rappo, 2003) Rappo, A. (2003): Fischaugenpro-jektionen mit distanzabhängiger Informa-tionsdichte für die kartographische Visualisierung auf kleinen Bildschirmen, Diplomarbeit, Geographisches Institut, Universität Zürich

(Barkowsky et al., 2000) Barkowsky, T., Latecki, L. J. and Richter, K.-F. (2000): Schematizing Maps: Simplification of Geographic Shape by Discrete Curve Evolution, in C. Freksa, W. Brauer, C. Hbel and K. F. Wender (Eds.), Spatial Cognition II, LNAI 1849, Berlin; Heidelberg: Springer-Verlag, 41-53 (Avelar, 2002) Avelar, S. (2002): Schematic Maps On Demand: Design, Modeling and Visuali-zation, Dissertation, Institut für Karto-graphie, Eidgenösische Technische Hochschule Zürich (Casakin et al., 2000) Casakin, H., Barkowsky, T., Klippel, A. and Freksa, C. (2000): Schematic Maps as Wayfinding Aids, in C. Freksa, W. Brauer, C. Hbel and K. F. Wender (Eds.), Spatial Cognition II, LNAI 1849, Berlin; Heidelberg: Springer-Verlag, 54-71 (Brunner, 2001) Brunner, K. (2001): Kartengestaltung für elektronische Bildanzeigen, in, Karto-graphische Bausteine, Band 19, Dresden: Technische Universität Dresden, Institut für Kartographie


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visualisation method cannot be used for all kinds of geographic information.

Fig. 19: Schematic map (Avelar, 2002) and topogram (Brunner, 2001)

The use of different LoDs and adaptive or smooth zooming tech-niques does not completely solve the problems arising from small displays, but offer helpful tools. Adaptive zooming is a technique for adapting content and LoD of a map automatically during zooming (Brühlmeier 2000). Cecconi (2003) proposes a conceptual framework for on-demand mapping. It is based on the use of dif-ferent LoDs in a multi resolution database (MRDB) in combination with real-time generalisation algorithms. Hampe and Sester (2002) developed strategies for real-time generalisation for mobile applications based on the MRDB approach. In continuing work related to the GiMoDig project they demonstrate how MRDBs can effectively be used to solve generalisation problems in mobile map services (Hampe et al. 2003).

(Brühlmeier, 2000) Brühlmeier, T. (2000): Interaktive Karten - adaptives Zoomen mit Scalable Vector Graphics, Diplomarbeit, Geogra-phisches Institut, Universität Zürich

(Cecconi, 2003) Cecconi, A. (2003): Integration of Cartographic Generalization and Multi-Scale Databases for Enhanced Web Mapping, Dissertation, Geographisches Institut, Universität Zürich

(Hampe and Sester, 2002) Hampe, M. and Sester, M. (2002): Real-time integration and generalization of spatial data for mobile applications, in, Geowissenschaftliche Mitteilungen, Heft Nr.60, Schriftenreihe der Studienrichtung Vermessungswesen und Geoinformation Technische Universität Wien

(Hampe et al., 2003) Hampe, M., Anders, K.-H. and Sester, M. (2003): MRDB Applications for Data Revision and Real-Time Generalisation, Proc. 21st International Cartographic Conference, Durban, South Africa, August 10-16, 2003


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3.2 Evaluation of approaches and solutions The projects and solutions described in the last section show some promising and partially feasible approaches for the display of geo-graphic information on mobile devices. However, most of them tackle the problem on a too isolated and detailed level. Navigation systems focus primarily on navigation functionality, although in recent times more efforts have been put on better visualisations (see Fig. 17). Work on graph schematisation, MRDB, adaptive zooming, and radial generalisation are important corner stones for the visualisation aspects of mobile information visualisation, but need to be integrated into a coherent framework. What is missing in almost all approaches is a coherent methodological framework for adaptive presentation of geographic information in a mobile context including alternative (not only visual) solutions for visuali-sation on mobile devices and multimodal presentation. This sec-tion detects the weaknesses of the different approaches and points to the respective chapters where some of the problems and inade-quacies are tried to overcome.

Most of the projects described above use maps to communicate geographic information on mobile devices. Yet, predominantly the used maps are in raster format. These raster maps are generally scanned paper maps which were designed for the paper medium. The map graphics is far too delicate for the size and resolution of the mobile device displays. It must be doubted, if an efficient usage of such maps on small displays is possible. Especially LBS were shouted as the killer application for 3G are still far away from offering usable map graphics. So far, their focus has been primarily on content and location information management. Nevertheless, the basic functions developed for LBS are crucial for mobile map-based services.

Another observation is that the development of solutions for mobile geographic information usage is technology and market driven and rarely methodologically founded. Most projects and commercial solutions implement what is technically feasible. It is not reflected whether it is sensible, useful or appropriate for the mobile environment. Chapter 4 introduces a new and more com-prehensive framework for mobile cartography combining different theories and approaches described so far in isolation and enlight-ening as a core feature the adaptation concept.

Being technology driven, most services do not focus on graphical quality and clarity. Instead in most services an ‘anything goes’ approach rules the visualisation of geographic information. Even if


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vector data is used, the maps are cluttered and difficult to read considering the complicated reading conditions in mobile envi-ronments. At least some producers apply design principles for screen maps resulting in more legible maps. However, these maps still do not use the whole potential of adaptation to the usage situation. Thus, new or enhanced methods for appropriate visuali-sations of geographic information on mobile devices are needed. Section 4.2.6 covers visualisation aspects and section 5.4 puts for-ward new methods.

The commercial background of LBS solutions is also an impedi-ment for a real individualisation of the information content and does not make use of the full potential and the information wealth in the Internet. The user will only get the information that a service provider has pre-selected and stored on a server. This situation is analogue to editorial of maps or tourist guides. Many approaches are targeted at a special user groups (service technicians, sales manager, etc.) with special needs and are not necessarily univer-sally valid. These services often serve marketing and advertisement purposes not always desired and tolerated by users. Another problem is that these services are not interoperable due to proprietary formats and technology.

In addition to the technology focus, most approaches concentrate too much on location as a context dimension. Although location is an important context parameter, it is not the only context dimen-sion. For effective mobile cartography, other context dimensions must be considered. The broader understanding of context and its value for mobile geovisualisation is examined in section 4.2.3.

With the exception of the positioning function (by use of GPS) in car navigation systems and city guide maps, the solutions do not offer egocentric maps. And even the spatial centring of the map around the user is only the simplest way. The concept of egocentric maps should be addressed in a much broader sense as accom-plished by approaches like LBS. It should extend the egocentric map approach to egocentric design, where the user is put into the centre of the whole information design and presentation. These egocentric presentations reflect the users’ demand for information and corresponding maps adapted to their needs. In addition to the label ‘egocentric’, these maps will be more personal and private. Egocentric maps have to put the user in centre, spatially, tempo-rally, and thematically.

In relation to the egocentric map approach adaptation is of major importance. The possibilities and components of adaptation within


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the process of visualising geographic information on mobile devices are investigated in chapter 5.

Although the existing solutions for visualisation of geographic information on mobile devices are far away from being satisfactory, the discipline of cartography has not yet taken the challenge to serve the needs of a more and more mobile informa-tion society. New information technologies and concepts, such as mobile computing, LBS, and adaptive systems, have not yet found their way into cartographic theory. Though there are concepts proposed for multimedia cartography and interactive cartographic visualisation systems, new aspects have been neglected so far. These aspects are user mobility (movement; speed), usage con-texts, activities, and events. Concerning the problem of the small displays most approaches developed in cartography, i.e. solutions known from desktop and web mapping, seem to fail in a mobile context under the severe restrictions mentioned above. Unfortu-nately there exist only rudimentary solutions for accessing and displaying geographic information on mobile devices and a theory for screen design targeted at mobile devices is missing up to now. It is the author’s conviction that for progressing in mobile geo-graphic information visualisation a broader understanding and a comprehensive framework of mobile cartography embracing all involved theories and concepts is crucial. The next chapter intro-duces this framework and explains the links between its building blocks. This serves as the base for the transfer of the adaptation concept to cartography for mobile users.


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Chapter 4

4 A new and comprehensive conceptual framework of mobile cartography

It is the framework which changes with each new technology and not just the picture within the frame. – Marshall McLuhan

4.1 Rationale for a mobile cartography

Cartography as many other disciplines has seen dramatic changes over the last dozen years. The advances in technology had and still have an enormous impact on the discipline. With the ‘digital revolution’ the branch of digital cartography has appeared. The Internet has offered new possibilities of map distribution. More recently, as the preceding chapters witnessed, new technologies like telecommunication and mobile computing are ready to be used. However, these technologies are only the prerequisites for mobility oriented cartography. The salient element of a mobile car-tography is its potential for adapting the way information is visualised. In the next section, the details of mobile maps and a comprehensive framework of mobile cartography will be elabo-rated.

Using these new technologies, maps can be transferred to and displayed on mobile devices. To start with, the author elaborates the characteristics of cartographic visualisations on mobile devices and tries to deduce the most relevant and specific attributes of mobile maps. A mobile map is here defined as a map or a map-like visualisation designed for the display on a mobile device. Many attributes of mobile maps can be found in other maps as well. An analysis of the characteristics of maps can be found in (Goodchild 2000, p. 4f.): maps are visual, flat, exhaustive, uniform in level of detail, static, generic, precise, and slow. Another list of

(Goodchild, 2000) Goodchild, M. F. (2000): Cartographic Futures On A Digital Earth (Keynote Address,19th International Cartographic Conference 1999, Ottawa), cartographic perspectives 36(Spring)


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characteristics of cartographic screen media is given by Heidmann (1999, p. 35): dynamism, interactivity, individuality, multifunction-ality, multimodality, multicoding, adaptivity, linkage, and ubiquity.

Table 5 shows the comparison of different map groups regarding the set of characteristics of mobile maps. It is evident that mobile maps primarily profit from a combination of known maps attributes. Printed maps – whether produced manually or digitally– are hardly changeable in their form. Yet, they are highly mobile. Internet maps or web maps allow a certain personalisation and adaptation, their distribution is easy and fast, they are up to date, and can incorporate multimedia and interactivity. However, Internet cartography is a priori not mobile. This also means that the potential for adaptation of web maps is rather limited.

Mobility of maps is not a new feature. For centuries maps have been mobile in the sense of being transportable or movable. The new opportunities digital technology and especially the Internet brought to cartography implied also the loss of mobility.

(digital) mobile maps

analogically or digitally produced printed maps

digital maps - offline

(CD-ROM)

digital maps - online (Web)

medium mobile - - positionable - - ( ) dateable - - content dynamic -

multimedia -

adaptable -

adaptive -

interactive -

location-dependently designable - ( ) ( )

time-dependently designable - ( )

usage mobile - - synchronised - -

location independent - - time independent ( ) usage situation quickly - - resources limited - - -

Table 5: Characteristics of different map groups



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A major advantage of mobile computing is therefore the combi-nation of all assets of digital technology with mobility. The real new momentum and at the same time the biggest challenge for cartography, however, is the ability to directly respond to the user’s mobility and provide new services for mobile users. The mobile computing paradigm and also the mobility of geographic information usage are characterised by the slogan “anything, anytime, anywhere”. This slogan shows a paradox: on the one hand thanks to mobile computing any information (anything) can indeed be accessed (almost) independently of location and time (anywhere und anytime), on the other hand it is not about any information, but it is about the selection and presentation of information dependent on location and time (and other factors). “The challenge in an information-rich world (in which human attention is the most valuable and scarcest commodity) is not only to make infor-mation available to people at any time, at any place and in any form, but to reduce information overload by making information relevant to the task-at-hand and to the assumed background knowledge of the users“ (Fischer 2001, p.65). The vision of a mobile cartography is to present the user always the right spatially related information at the right moment at the right place. Who-ever the user is, he/she will always get the information relevant to his/her current context and interests, knowledge and skill level, presented in a way he/she is used to. In contrast to traditional car-tography this means the location of the user can be determined by methods described in section 2.2.1. This offers the chance to tailor geovisualisation to this location and other parameters (e.g. time) defining the user’s context as to be discussed in section 2.1.3. The use of such a system must not be complicated. It would be usable at hand, and being self-explanatory. The complex functionality is hidden from the user and as many tasks as possible are automati-cally performed, though interaction is always possible when needed. Mobile users having to perform spatial tasks or having spatial questions of all sorts will be given assistance through mobile cartography. This understanding easily fits the concept proposed by Aronoff (1991) where three categories are distin-guished: the questions category, the function category, and the an-swers category. It also fits the web service concept discussed in section 2.2.2. Hence, the challenging momentum of this vision for cartography consists in an adequate adaptation of geovisualisation to mobile usage situations with the overall goal to guarantee usability.

(Aronoff, 1991) Aronoff, S. (1991): Geographic Informa-tion Systems: A management perspective, Ottawa: WDL Publications

(Fischer, 2001) Fischer, G. (2001): User Modeling in Human-Computer Interaction, User Modeling and User-Adapted Interaction (UMUAI) 11(2): 65-86


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In spite of the great potential and chances of the vision described above, these new possibilities have not yet been fully addressed in cartography. Although different concepts of information tech-nology, GIS and web mapping introduced some substantial innovative issues to cartography, none of them fully covers the scope of cartography in a mobile context. These fields have all their own accentuation (market, technical issues). A comprehension of the concept of mobile cartography and its scope is still missing. It is therefore time to bring these divergent views into one coherent and convergent concept of mobile cartography, which can be defined as theories, methods, and technologies of dynamic and adaptive cartographic visualisation of geographic information and its interactive use on mobile devices where visualisation is adapted to either one or all components of the actual usage context (loca-tion, time, user, activities, information, and system).

As in all new and developing fields, the terminology is not so clear and fixed yet. Beside mobile cartography a couple of other terms are in use. Some of them stress other characteristics of maps on mobile devices, some come from other disciplines. Tele-Cartography means the exchange and transmission of spatial information through cartographic products that are transmitted by telecommunication technologies and are accessible by mobile query and display devices (Gartner 2000). The original sense of telos referring to remote, dislocated is valid as well for Internet carto-graphy. TeleCartography focuses primarily on technical aspects, mainly transmission technology, i.e. telecommunication techniques. The use of mobile devices implicitly indicates a mobile usage situation. However, there is no reference to adaptation in the defi-nition. The same critique is true for terms like wireless mapping, where transmission technology is emphasized. Another well established concept are Location Based Services. Mobile maps can and definitely will be used for LBS, but one can easily think of LBS without any cartographic visualisation.

On the one hand this work uses the term mobile, since it reflects the user’s mobility in three different dimensions: the mobile media, the mobile usage, and the mobile content. Attributes like wireless are too narrow and put the emphasis rather on technology. On the other hand the thesis uses the term cartography to resolutely distinguish the concept from mobile mapping or mobile GIS where the focus is on real-time graphic rendering, analysis or data capturing on site without appropriately considering graphical design. However, it must be stressed that in the background several more or less

(Gartner, 2000) Gartner, G. (2000): TeleKartographie, GeoBIT(4): 21-24


61

complex GIS analytical functions (e.g. routing) must be available to serve the visualisation front-end. In addition, it is not necessary to call the concept mobile digital cartography, since it would not work in an analogue mode and also, because there has never been a mobile ‘analogue’ cartography – neither as a term nor as a method to be dis-tinguished from. This also seems to be another indicator that such an independent research field has never existed in cartography so far. Thinking of the rather static nature of traditional cartographic products for mobile users this is not surprising.

The core element of the mobile cartography concept is adapta-tion. An adaptive geovisualisation service is capable of adapting to a specific user, his/her activities, the system in use, and the current information demand. The first who mentioned this basic under-standing was (Bollmann 1996, p. 35). He stated that a map is representing communication sequences in the context of activities attributing to the map the role of a dynamic system. A map in such a sense is an immediately available medium adapting itself to the user’s goals and activities.

For an extended discussion of issues covered in this chapter and those to be covered in the next chapters see (Reichenbacher et al. 2002; Reichenbacher and Meng 2003).

4.2 A framework of mobile cartography To capture the basic ideas of the vision sketched above, the author introduced a first conceptual framework of mobile cartography in (Reichenbacher 2001). This framework showed the major building blocks of mobile cartography in focus. This chapter has elaborated so far the core of mobile cartography: adaptation of geographic information visualisation to the mobile usage situation. The framework of mobile cartography proposed here accounts for that fact. Fig. 20 shows the refined conceptual framework. The key components are context, information, user interface, and visualisa-tion. The original framework also included technology. As discussed earlier, technology is regarded as the basic enabling system working in the background. It can be attributed to the con-text. The components shown in Fig. 20 can be arranged according to the widely used design pattern of Model – View – Control. The basic idea is to separate the data from presentation and the logic that controls how the data is displayed. These three axes are aligned horizontally in Fig. 20. A second grouping can be achieved by using the primary adaptation dimensions: adaptation objects (the elements to be adapted), adaptation target (the elements which the adaptation objects are adapted to), and the adaptors (the

(Bollmann, 1996) Bollmann, J. (1996): Kartographische Modellierung - Integrierte Herstellung und Nutzung von Karten-systemen, Kartographie im Umbruch. Tagungsband zum Kartographenkongress Interlaken 1996, Interlaken

(Reichenbacher et al., 2002) Reichenbacher, T., Angsüsser, S. and Meng, L. (2002): Mobile Kartographie - eine offene Diskussion, Kartographische Nachrichten(5)

(Reichenbacher and Meng, 2003) Reichenbacher, T. and Meng, L. (2003): Themenheft 'Mobile Kartographie', Kartographische Nachrichten (1&2)

(Reichenbacher, 2001) Reichenbacher, T. (2001): The World In Your Pocket - Towards A Mobile Cartography, Proceedings The 20th International Cartographic Conference, Beijing, China, August, 6 - 10, 2001


62

methods that actually perform the adaptation). These dimensions are aligned vertically in Fig. 20. The figure also shows that the user performing any activities is set in a context. The same applies for the information demand and the geographic information usage in the form of perceiving visual representations of the information.

view

visualisation

control

user interface

user

activities

adaptation

model

information

context

target

objects

answer /presentation

question /request

(4.2.1)

(4.2.2)

(4.2.3)

(4.2.4) (4.2.5) (4.2.6)

location informationtime system

Fig. 20: Conceptual framework of mobile cartography

The main goal of the mobile cartography approach is to offer visualisations of geographic information with the greatest possible relevance to the mobile user. Relevant is defined in the Collins English Dictionary as “having direct bearing on the matter in hand”. This definition already embodies the importance of the user. It is the user (the ‘hand’) that is the object of relevancy. The information and its visualisation have to be relevant to the user. In that sense it has also to be relevant to the context the user belongs to and its dimensions (location, time, activity, information, system, etc.). In the remainder of this chapter the major components of mobile cartography and their relationships as outlined in the framework are explained in more detail. Firstly, the role of the user in mobile cartography with a special focus on the influence of mobility is clarified, followed by an attempt to capture the basic activities of mobile users. Secondly, the importance of context for mobile cartography is enlightened and the different dimensions of usage context and their possible modelling are described. The sec-tion on information looks on issues of information structure, quality, demands and relevance. An analysis of implications of


63

visualisation is preceded by a section investigating the role of the user interface in mobile cartography. The role of adaptation in the mobile cartography framework is to maximise the relevancy by modifying the visualisation in respect and is extensively examined in chapter 5. At the end of this chapter the relationships of the framework components are summarised. 4.2.1 Mobile users

The user plays the central role in mobile cartography. The whole effort of mobile cartography – and cartography in general – is directed towards the user. The following analysis covers three different user related topics: information demand, mobility, and individualisation.

It is not questioned that a mobile user will sooner or later have a spatial information demand. This information can be expressed in different types of questions as depicted in Fig. 21 (map from Neudeck 2001). The information demand of mobile users is studied in more detail in the section on information. For the scope of this research the information demand arises in a mobile envi-ronment, i.e. the information required is related to the user’s mobility.

identification

what is the name of this town?

Sonthofen

location

where is the train station?

xy = 5422, 8917

trends

what has changed?

forest coverage

pattern

what relation exists

road crosses rivertopology

between road andriver network?

what is the shortest routebetween A and B?

start A, turnleft ...

path/route

Fig. 21: Typical spatial questions (adapted from Kraak and Ormeling 1996)

When speaking of users and mobile cartography it is worth dis-cussing some issues of user mobility. The meanings of mobility range from just being in motion, changing locations or travelling to social mobility like changing roles or social classes. This is also reflected by different meanings of mobile (Merriam-Webster’s Collegiate Dictionary): capable of moving or being moved: movable; changeable in appearance, mood or purpose: adaptable, versatile; moving habitually or occasionally from one region or climate to another: migratory; characterized by the mixing of social groups. As touched on in section 4.1 it has to be discerned what/who is mobile? Is it solely the user, the device (medium) or

(Kraak and Ormeling, 1996) Kraak, M. J. and Ormeling, F. J. (1996): Cartography: visualization of spatial data, Harlow: Longman


64

both? In mobile telecommunications the corresponding mobility types are called personal and terminal mobility. In the same man-ner discrete mobility is distinguished from continuous mobility. In the former case a service is only available at certain places (e.g. access points like office or home). In the latter case the service is continuously available during movement. Portability is a special form of discrete mobility where the user can take his/her device from one access point to another (Van Thanh 2002).

To study the influences of user mobility on mobile cartography it is necessary to take a more systematic approach to movement as proposed for example by Coffey (1981, p. 153ff.): Structure and movement are of dualistic nature. Movement effects structure and structure constrains movement. Mobility is also a matter of scale. At a large scale pure body movement can be considered as mobil-ity, whereas at a very small scale, i.e. from a large distance, the same could be observed as static. A further typification of move-ment is related to medium and mode. The medium represents the base for the movement, i.e. asphalt, water or steel. Every medium possesses a certain friction influencing the movement. The mode affects this influence of the medium on the movement. The struc-ture of movement can be analysed in terms of geometry, i.e. the distance and orientation of the movement, the shape generated by the movement, the arising patterns, absolute and relative locations of start, middle, and end points of movements. Moreover, topol-ogy plays an important role. Additionally, several movements can build a movement hierarchy that again is the dualism of a structure hierarchy. Finally, the intrinsic characteristics of movement per se can be isolated: directionality, continuity, and permanence. Movement can be uni-directional (e.g. A->B or B->A), one-way (e.g. only A->B, but not B->A) or bi-directional (A->B and B->A). The characteristic continuity has been described in the paragraph above. A discreet movement involves stops. Permanence reflects the temporal aspect of movement. It can only be a temporary or a permanent matter (which is rather the case for natural movements than for moving human beings). Models of movement can be deterministic or stochastic. For research on modelling movement patterns and deferring user activities see (Mountain and Raper 2002).

The spatial scope of mobility is another factor that influences for example the choice of mobility medium and mode. Local mobility could pragmatically be defined as mobility within walking distance.

(Coffey, 1981) Coffey, W. J. (1981): Geography - Towards a General Spatial Systems Approach, London: Methuen & Co

(Mountain and Raper, 2002) Mountain, D. and Raper, J. (2002): Modelling human spatio-temporal behaviour: A challenge for location-based services, Proceedings AGI 2002, London

(van Tanh, 2002) Van Thanh, D. (2002): Introduction to Mobility. http://www.item.ntnu.no/~thanhvan/ doc/MobilityForelesning.PDF


65

One consequence of mobility, or more precisely the possibility of mobile geographic information usage during mobility, is an increasing demand for individualisation. What has been introduced by the concept of on-demand mapping goes a step fur-ther. It is technically possible and due to the inherent characteristics of mobility (e.g. changing contexts; different move-ment modes) often necessary to individualise the map presentation. Here, any adaptation or generation of a map requested or triggered by a single user is understood as an individualisation.

Each human being is unique, an individual. We all differ from each other, though maybe not that much. These individual differ-ences may play an important role in using geographic information, but also in many other aspects of life. These differences can be more general characteristics related to the personality or more spe-cific characteristics that may vary from one system usage or usage situation to another.

The fact that knowledge about the personality and cognitive abilities are of help for designing systems for a special user group has been acknowledged by Shneiderman (1987). Benyon (1993, p. 6) points out that the interaction with a system can be seen as a cognitive task and hence individual differences in cognition pref-erences or abilities are to be expected. Such cognitive preferences and abilities are relatively stable human characteristics which change very slowly over time. However, it seems to be difficult to isolate relevant user attributes which might have an influence on the visualisation and the adaptation of it.

A more promising approach is to isolate a few typical user types, stereotypes “… to design methods so they can be adjusted to the cognitive characteristics of the individual user” (Slocum et al. 2001, p. 70). One approach to find such stereotypes is the person-ality theory, a branch of differential psychology. A typology of personalities has first been introduced by the psychologist C.G. Jung in 1921 who distinguished four dichotomies (Jung 2001): extroversion – introversion; thinking – feeling; sensing – intuition; judgement – perception. Based on Jung’s typology Isabel Briggs and her mother Kathryn Myers developed the Myers-Briggs Type Indicator (MBTI) that distinguishes 16 types as a combination of the four dichotomies. This type can relatively easily be determined and can act as a rough stereotype, since user characteristics that build a personality are fairly constant and also have an impact on the usage of a system.

Further reading:

(Beck and Beck-Gernsheim 2002) Beck, U. and Beck-Gernsheim, E. (2002): Individualization: Institutionalized Individualism and its Social and Political Consequences, London: SAGE Publica-tions

(Searby 2003) Searby, S. (2003): Personalisation - an overview of its use and potential, BT Technology Journal 21(1): 13-19

(Shneiderman, 1987) Shneiderman, B. (1987): Designing the User Interface, Reading: Addison-Wesley

(Benyon, 1993) Benyon, D. (1993): Accommodating Individual Differences through an Adap-tive User Interface, in M. Schneider-Hufschmidt, T. Kühme and U. Malinowski (Eds.), Adaptive User Interfaces: Principles and Practice, Amsterdam: North-Holland, 149- 166

(Slocum et al., 2001) Slocum, T. A., Blok, C., Jiang, B., Koussoulakou, A., Montello, D. R., Fuhrmann, S. and Hedley, S. (2001): Cognitive and usability issues in geovisu-alization: a research agenda., Cartography and Geographic Informa-tion Science 28(1): 61-76

(Jung, 2001) Jung, C. G. (2001): Typologie, München: Deutscher Taschenbuch Verlag GmbH & Co. KG


66

An even more universal stereotype is a mobile user stereotype that can be formed, because despite all individual differences there are also a few things all mobile users have in common. Mobile users are under time pressure, need to make quick decisions, are more easily distracted, have to process an enormous amount of stimuli, are less predictable, are limited in their interaction with a device, etc.

This stereotype can be taken as a rough model for adapting geo-visualisation. It certainly needs to be extended through more fine-grained user models; however, this is beyond the scope of this thesis. 4.2.2 Mobile activities

An activity here is defined as a motivated sequence of coherent actions carried out at a specific location for a certain time. For example, dining is an activity carried out at a restaurant. As mentioned above, there are many different activities mobile users conduct and for which appropriate information visualisation tech-niques have to be developed. Apart from their motivation and inherent structure these activities also have a spatial scope. In two research projects, Fraunhofer SAiMotion (Heidmann and Hermann 2003) and WebPark (Edwardes et al. 2003b), the range or scope of activities and information demand has been analysed. The ranges of activities are related to ranges of context. In Fig. 22 the following three major ranges are distinguished:

• immediate surroundings: information supporting identification of objects

• region of activity: context information relevant for dyna-mism of user activities

• background space: global, descriptive overview informa-tion supporting the planning of activities

Information on global context, i.e. on a macro scale requires small scale maps to provide the necessary overview, whereas for local context, i.e. on a micro scale large scale maps showing objects for direct references to the real environment are more appropriate. The regional context, i.e. on a meso scale, is between the two and sets the main context for activity planning. In addition the scope of each region also depends on the mobility medium. It makes a big difference whether one travels by bike, car or plane. The range of these media differs substantially, thus the size of the different re-gions.

(Heidmann and Hermann, 2003) Heidmann, F. and Hermann, F. (2003): Visualisierung raumbezogener Informa-tionen für ultraportable mobile Systeme, in, Visualisierung und Erschließung von Geodaten - Seminar GEOVIS 2003, 26. bis 27. Februar 2003, Universität Hannover, Kartographische Schriften, Band 7, Bonn: Kirschbaum Verlag, 121-131

(Edwardes et al., 2003b) Edwardes, A., Burghardt, D. and Weibel, R. (2003b): WebPark - Location Based Services for Species Search in Recreation Area, Proceedings 21st International Cartographic Conference, Durban, South Africa, August 10-16, 2003


67

Fig. 22: Spatial scope of activities (adapted from Heidmann and Hermann 2003, p. 126)

Comparing services from different LBS providers brings a certain insight into possible demands of mobile users and the activities they might need support for. Such services, as for instance pro-vided by the company gate5, are people finder, vicinity search, content search, category search, routing search, event guide, per-sonal info manager, group activity manager, activity recommender, city guide, tour guide, news magazine.

This enumeration shows an increasing importance of managing lifestyle activities in space and time. Activity programmes, i.e. lists of activities to be performed in a specific time period, e.g. eating, working, or going in a concert, need to be scheduled. Scheduling of activities include decisions about location, time, and sequence of activities, how to connect them, and how to embed them in exist-ing programmes (Wang and Cheng 2001).

Besides regarding these services, an analysis of literature on map usage functions and GIS functionality draws a clearer picture of relevant mobile user activities. Table 6 summarises relevant spatial questions, map usage tasks, GIS operations and examples of mobile services.

Location services

www.gate5.de.

http://www.vodafone.de/kundenbetreuung_services/unterwegs/31326.html

(Wang and Cheng, 2001) Wang, D. and Cheng, T. (2001): A spatio-temporal data model for activity-based transport demand modelling, International Journal Geographical Information Science 15(6): 561-585


68

Questions / Problems Tasks / Actions (GIS) Operations Services (Solutions/Answers)

locating where am I ? a) where is Mum? a) where is my car? a) where is Karstadt? a)

am I near X ? am I left or right of X?

to locate c)

position a) geocoding e)

locate person b) locate objects b)

navigating how do I get there / to … ? what is the fastest way to ..?

route a) slope d), aspect d) viewshed d) centrality/ connectedness f)

trip templates b) suggestions to travel-lers based on destination and geography b) weather sensitive planning / guidance b) travel across areas without roads b) route commentary b) navigation with real-time map display b) navigation with real-time 3D display b)

searching where is the nearest … ? what is near of …? c) what is the distance to …? c) what is the spatial distribution of …? c) what is the nearest visible landmark?

to position c) to define c) to find order, patterns c) to contemplate spatial context c)

proximity d)

distance f) area f) relationship f) distribution a)

suitability f) buffer d) corridor d) overlay d) thiessen/voronoi d) presentation f)

service discovery b) location-sensitive pushed information (warnings, informa-tion) b) location-sensitive message delivery b) location-sensitive appointments b) group travel support b) guidance to parking b)

Identifying who is there? what is there? c) what is that? b)

to recognize c) to identify c)

directory a) selection f) thematic search d) spatial search d)

how much is there? c) To quantify/ esti-mate c)

measurements d)

Checking can someone help me to …?

search for help accident/incident support b)

what is the state of …? to determine changes c)

traffic information delivery b)

what happens at … ? to establish trends c) to detect proc-esses c)

inventory f) description f) pattern d) trend f) frequency f)

will I be in time? trend f) tracking of progress to an appointment b)

Table 6: Relationship between spatial user actions and GIS operations

However, there is no consistent taxonomy of mobile spatial actions, but from the analysis of the services mentioned above and the literature review, the following elementary actions to which any more concrete activity could be attributed can be

a) (SUN 2001a) SUN (2001a): Java Location Services: The new Standard for Location-Enabled E-Business, White Paper. http://www.jlocationservices.com/company/Sun/JavaLocServBR_R4.pdf b) (MAGIC 2000) MAGIC (2000): Introduction to MAGIC Services, Technical Information White-paper, MAGIC Services Forum. http://www.magicservicesforum.org/tech/ tech_info_whitepaper.doc c) (van Elzakker 2001) van Elzakker, C. (2001): Map Use Tasks in Regional Exploratory Studies, Pro-ceedings 20th International Cartographic Conference, Beijing, China, August 6-10, 2001 d) (Albrecht 1996) Albrecht, J. (1996): Universal GIS operations for environmental modeling, Proceedings 3rd International Con-ference on Integrating GIS and Environmental Modeling, Santa Barbara (CA) e) (Niedzwiadek 2000) Niedzwiadek, H. (2000): Eye on the Future of Java Location Services, Pro-ceedings Mapworld 2000, San Antonio, TX, April 30 - May 3, 2000 f) (Oracle 2001)

Oracle (2001): Leveraging Location-Based Services for Mobile Applications, Technical White Paper, Oracle. http://www.jlocationservices.com/company/Oracle/LS_Tech_wp.pdf


69

distinguished. The elementary actions listed in Table 7 are locating, navigating, searching, identifying, and checking.

act

ion

qu

est

ion

s

ob

ject

ive

op

era

tion

s

serv

ice

p

ara

mete

r

sup

port

ori

en

tati

on

&

loca

lisa

tion

loca

ting

wher

e am

I?

wher

e is

{per

son|

obje

ct}?

loca

lise

peo

ple

and

obje

cts

posi

tionin

g

geo

codin

g

geo

dec

odin

g

del

iver

posi

tion o

f per

sons

and o

bje

cts

n

avig

ati

on

navi

gatin

g thro

ugh

space

, pla

nnin

g a

route

how

do I g

et

to

{pla

ce n

am

e|

addre

ss|

xy}?

find the

way

to a

des

tinatio

n

posi

tionin

g

geo

codin

g

geo

dec

odin

g

routin

g

del

iver

route

s and

navi

gatio

n inst

ruct

ions

se

arc

h

searc

hin

g for

peo

ple

and o

bje

cts

wher

e is

the

{nea

rest

| m

ost

rel

evant|

&}

{per

son|

obje

ct}?

searc

hin

g for

peo

ple

and o

bje

cts

mee

ting

the

searc

h c

rite

ria

posi

tionin

g

geo

codin

g

calc

ula

ting d

ista

nce

and a

rea

findin

g r

elatio

nsh

ips

dis

cove

r ava

ilable

se

rvic

es;

find p

erso

ns/

obje

cts

id

en

tifi

cati

on

iden

tifyi

ng a

nd

reco

gnis

ing p

erso

ns

or

obje

cts

{what|

who|

how

m

uch

} is

{her

e|

ther

e}?

iden

tify

peo

ple

and

obje

cts;

quantif

y obje

cts

direc

tory

se

lect

ion

them

atic

/ sp

atia

l se

arc

h

del

iver

(se

mantic

) in

form

atio

n a

bout

per

sons/

obje

cts

even

t ch

eck

chec

king for

even

ts;

det

erm

inin

g the

state

of obje

cts

what happen

s {h

ere|

th

ere}

?

know

ing w

hat

happen

s; k

now

ing

the

state

of obje

cts

del

iver

obje

ct s

tate

in

form

atio

n a

nd e

vent

info

rmatio

n

coord

inate

obje

ctaddre

sspla

ce n

am

e

startin

g p

oin

t,des

tinatio

n p

oin

t,and w

ayp

oin

tsas

loca

tions

orien

tatio

n in s

pace

loca

tion

are

a/r

adiu

sobje

ct/c

ate

gory

obje

ct

time

loca

tion

obje

ct

¶?

loca

ting ?

�)

nav

igat

ing ?

ýB

sear

chin

g ?�

D identify

ing ?

c̀heck

ing

findin

g the

way

thro

ugh s

pace

findin

g r

elev

ant

obje

cts;

findin

g p

eople

info

rmatio

n a

bout

real w

orld o

bje

cts

of

the

usa

ge

situ

atio

n

findin

g r

elev

ant ev

ents

;in

form

atio

n a

bout th

est

ate

of re

al w

orld

obje

cts

in the

usa

ge

situ

atio

n

Table 7: Elementary mobile user actions with spatial relation


70

These basic actions can be assembled in a modular manner to activities (Fig. 23). In general an activity is guided by a motivation. To satisfy the motivation most likely some spatial problems or spatial questions will have to be solved or answered. To do this, the elementary actions with their associated goals are performed in a certain combination. According to activity theory, this process involves several operations. It is important to separate the goals and plans involved in a spatial user action (e.g. navigation: get from here to point A) from the operations needed to achieve them (direction following, translation of position on the display to the real world environment, etc.). Services in general are to help the user to achieve his/her action goals and assist him in the execution of the necessary actions to be taken. A service assisting a mobile user should answer or solve the questions/problems at hand and be capable of adapting itself to these different actions and associ-ated goals. Instead of relying on a user model only, the activities with their associated goals, user roles, and information needs are more likely to be the common ground for adapting to.

locatingnavigating

searching

checking

going to cinema

Fig. 23: Modular construction of activities based on single actions

The isolation of elementary, mobile, spatially related actions aims at being able to map these actions with related goals (and spatial questions) to supporting geovisualisation services. This makes it possible to adapt these services later to the specific action. Again, these elementary services can be combined or bundled to higher level services. Since the objective is to simplify the problem space of possible adaptations, the proposed categorisation of actions contains certain overlaps between actions. In addition not all


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actions are on the same aggregation level. Locating, for example, is far more elementary and specific than searching.

An alternative approach to isolating elementary spatial user actions is the application of patterns. In software design and HCI design patterns are increasingly used to provide developers solu-tions to recurring standard problems. Transferred to mobile geographic information usage situations, several recurring, typical, spatially related problems could be described in patterns.

The activities a user wants to accomplish when being mobile are highly dependent on context and vice versa. User activities shape the context and specific contexts do not allow certain kinds of activities. Knowing some aspects of the current context helps to reduce the number of possible activities. The next section covers the features of context important for mobile cartography.

The development of a geoservice adapting to the current user activity requires knowledge about this activity. An automatic identification of the user’s activity is very difficult. First attempts in detecting mobile user activities have been made by Mountain and Raper (2002). They try to model mobile user activities from observ-ing spatio-temporal behaviour. By finding similar patterns conclusions for activities can be drawn. This already gives a hint that a learning component will be necessary for any progress in that direction.

In the section on activity theory the fact that individuals perform their actions in a specific role has been emphasized. The role a user is acting in sets the context and a given context can enable or dis-able certain roles. To better fit a service to the user’s needs, knowledge about the user’s role is crucial. Thus a typology of ele-mentary user roles in mobile environments is required. Kristoffersen and Ljungberg (1999) distinguish three ‘modalities’ of mobility which can also be understood as user roles: travelling, visiting, and wandering.

As stated earlier, the performance of mobile activities is dependent on information. It will also rely on fast and efficient communication of this information realised as visualisations. Mobile maps should support the user in performing these activities. The section on visualisation will sketch a minimal set of functions and visualisation capabilities a mobile map must provide to achieve this objective.

(Mountain and Raper, 2002) Mountain, D. and Raper, J. (2002): Modelling human spatio-temporal behaviour: A challenge for location-based services, Proceedings AGI 2002, London

(Kristoffersen and Ljungberg, 1999) Kristoffersen, S. and Ljungberg, F. (1999): Mobile use of IT, Proceedings 22nd Information Systems Research Seminar in Scandinavia Conference (IRIS 22)


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4.2.3 Mobile context

It is no surprise that the most prominent adapted services for mo-bile users are LBS, since location is the most important context dimension concerned with mobility. However, there are many more facets of context which can partly be derived from location. Examples of such context parameters are time, weather or medium of transport. There are also technological context aspects, such as network quality, device characteristics and many more. Further-more several context dimensions can be separated: physical context, system context, semantic context, social context etc.

user

activities

informationsystem

situation

physical conditions

co-locatedobjects

events

Fig. 24: Dimensions of the geographic information usage context

As pointed out in section 2.1, context is an ample field. For the purpose of mobile cartography context is understood as the more general concept embracing the more specific dimensions like situation, user, activities, information, and system (see Fig. 24, Fig. 25, and Table 8). These context dimensions are not inde-pendent, but have many and sometimes quite complex inter-relationships as illustrated in Fig. 25. The major difficulty with context here is to select from the vast amount of possible context dimensions or parameters those that are relevant for mobile car-tography and have a significant impact on the mobile geospatial information usage. Nivala and Sarjakoski (2003) list apart from the dimensions mentioned so far purpose of use, social context, cultural context, physical context, orientation context, and naviga-tion history context. Table 8 gives a summary of the main dimensions of context in literature to mobile geographic informa-tion usage.

(Nivala and Sarjakoski, 2003) Nivala, A.-M. and Sarjakoski, L. T. (2003): Need for Context-Aware Topographic Maps in Mobile Devices, Proceedings 9th Scandinavian Research Conference on Geographic Information Science ScanGIS’2003, Espoo, Finland


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(Graham and Kjeldskov 2003)

(Dix et al. 2000)

(Nivala and Sarjakoski 2003)

(Reichen-bacher 2003)

Where Position (ab-solute)

Physical Con-text Location Position

Where Location (rela-tive)

Physical Con-text

Orientation Location

When Time Time Time What else Objects pre-

sent System Context / Infrastructure Context

System Informa-tion Technol-ogy

What task Activity Domain Con-text

Activity

Who User Domain Con-text

Purpose of use User Social

User

What con-ditions

Physical Envi-ronment

Physical Con-text

Physical sur-roundings

Informa-tion

What cul-ture

Domain Con-text

Cultural

Table 8: Dimensions of context in mobile cartography

Situation as the core of context is a function of location and time and is understood here in the original sense (Lat. situs) of being situated, i.e. placed in a spatio-temporal reference system which points to the (rest of the) context at hand. It should not be mixed up with the meaning of situation in the definition of Dey and Abowd (1999, p. 3f.). There it denotes the circumstances or environment. Situation, however, is a combination of Dey and Abowd’s context types, location and time. The situatedness of the user provides the context at hand. The reason for distinguishing situation and context is that – in the strict sense of LBS – adapting can be directed only to the situation, i.e. location and time or in a more ample manner to a wider context.

contextactivity

user

system

situation

device in usesystem functionsinfrastructure availablenetwork type & bandwidth

identitypreferencesknowledgeskillsroles

spatio-temporal reference:location & time

informationpresent geoobjectsstates of geoobjectseventsinformation demands

actions goalsactivities objectivesroles

performs

meta-informationrulesconstraintsrelationships

assumes

takes placeinis in

is availablein

has access to

can senserequires

Fig. 25: Generic context model for mobile cartography

(Graham and Kjeldskov, 2003) Graham, C. and Kjeldskov, J. (2003): Indexical Representations for Context-Aware Mobile Devices, Proceedings IADIS Internat. Conference on e-Society, Lisbon, Portugal, June 3-6, 2003

(Dix et al., 2000) Dix, A., Rodden, T., Davies, N., Trevor, J., Friday, A. and Palfreyman, K. (2000): Exploiting Space and Location as a Design Framework for Interactive Mobile Systems, ACM Transactions on Com-puter-Human Interaction 7(3): 285-321

(Nivala and Sarjakoski, 2003) Nivala, A.-M. and Sarjakoski, L. T. (2003): Need for Context-Aware Topographic Maps in Mobile Devices, Proceedings 9th Scandinavian Research Conference on Geographic Information Science ScanGIS’2003, Espoo, Finland

(Reichenbacher, 2003) Reichenbacher, T. (2003): Adaptive Methods for Mobile Cartography, Proc. 21st Internat. Cartographic Conference, Durban, S. Africa, August 10-16, 2003

(Dey and Abowd, 1999) Dey, A. K. and Abowd, G. D. (1999): Towards a Better Understanding of Context and Context- Awareness, Tech-nical Report, GIT-GVU-99-22, Georgia Institute of Technology, Atlanta (GA)


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Location information is related to a position and denotes different kinds or levels of granularity (e.g. point coordinates, addresses, place names, regions) with distinct ranges of values. The granu-larity required for specific activities or information demands varies substantially. It is worth mentioning that the majority of services will not need accuracies in the millimetre and centimetre range, but of several meters. Although not always feasible it is assumed that these different forms of location information are convertible by methods like geo-coding, geo-decoding, information overlays etc. An alliance founded in 2000 by Nokia, Ericsson and Motorola, called Location Interoperability Forum (LIF), established standard location protocols for the exchange of device locations. The LIF is now part of the Open Mobile Alliance (OMA), an organisation of 100 companies aiming at developing an open framework for LBS. Another player in the location domain is the Open GIS Consor-tium that offers a standard with the OpenLS framework (sec. 2.2.2). Apart from the location the orientation of the user (bearing) is an important context factor. The device orientation can for instance be determined with an electronic compass or kinematic GPS.

For time information the same granularity differences as for loca-tion can be identified. Time could for instance represent exact sys-tem time, day time, season, etc. This temporal granularity affects the way the system or service can react to a user request. Of course, the counterpart geographic information must also be temporally modelled.

The user and the activities he/she is performing are situated, hence dimensions of the context. Some authors see the modelling of the user in its own right. This user model (UM) approach is mostly taken for web content adaptation. Here it is part of the context model. As for the other dimensions, for the user in par-ticular the question arises which characteristics need to be modelled or, in other words, which attributes are important and relevant for the mobile geographic information usage and the adaptation to it. Dransch (2003) offers a useful framework for modelling geographic information users based on activity theory.

Activities are per definitionem embedded in a context and thus belong to the context. At an initial stage it is reasonable to establish a straightforward mobile activity taxonomy in the manner described in the preceding section. For a given context it is also important to know which activities are possible, allowed, appro-priate etc. This refers to the more difficult task of modelling rules and constraints in contexts. Another aspect connected to activities

OMA (LIF):

www.locationforum.org/

www.openmobilealliance.org

OGC:

www.opengis.org

MAGIC:

www.magicservicesforum.org

(Dransch, 2003) Dransch, D. (2003): Konzepte zur Modellierung der Nutzer von Geovisu-alisierungs-Systemen, in, Visualisie-rung und Erschließung von Geodaten - Seminar GEOVIS 2003, 26. bis 27. Februar 2003, Universität Hannover, Kartographische Schriften, Bonn: Kirschbaum Verlag, 103-110


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is the social dimension, i.e. the fact whether the activity is per-formed alone or in a group, if other people are involved or affected. This kind of information could also be modelled in the user dimension.

The information in mobile cartography cannot only be the source for visualisation, but also a context dimension of its own, describ-ing the context of objects inside the spatial context scope, e.g. building types. This type of contextual information is termed co-located geospatial objects. In linguistics collocation refers to the common, meaningful appearance of words. Similarly, in space some objects commonly tend to be present more often than others. For instance, the presence of a church indicates the presence of a churchyard. Discrete geospatial objects can be modelled with the collocation approach, i.e. the presence of a geospatial object could be deferred with a certain probability/likelihood from the observa-tion of another geospatial object. For continuous data, i.e. continu-ous fields (e.g. temperature), spatial autocorrelation can be applied. Yet, it is often enough to derive a set of co-located geo-spatial objects through basic GIS overlay functions such as select_within_distance. Advanced operations can also include the cal-culation of visibility (is object X visible from the user’s position?). Clearly the attributes and states of these co-located geospatial objects are of utmost interest, since they considerably characterise the context. This information partially overlaps with another type of contextual information, the physical parameters (e.g. tempera-ture, humidity, noise level, etc.).

The characteristics of the system in use constitute another im-portant context dimension that must not be underestimated. Device or network characteristics have a substantial influence on the way information should best be transmitted and visualised. One standard for describing device capabilities is the Composite Capabilities/Preference Profile (CC/PP). CC/PP is an exchange protocol specified by the World Wide Web Consortium and defined within the resource description framework (RDF).

It is at least as important as to identify the relevant context dimensions as it is to model the relationships between them and to describe the rules or constraints valid for a context. For instance, the physical context (e.g. the weather) has an influence on possible activities (e.g. ice skating on a lake during summer is not appro-priate). Activities also set up a context, e.g. riding a bus or shopping. Thus the elaboration of an activity typology can help defining a corresponding context typology.

CC/PP: www.w3.org/Mobile/CCPP/


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The example code below shows an XML representation of the context parameters described before: <context> <location> <x>4468503.88</x> <y>5332375.59</y> </location> <time>14:37:52</time> <date>20031022</date> <user>Tumasch Reichenbacher</user> <activity>navigating</activity> <information> <collection> <gml:boundedBy> <gml:box> <gml:coord> <gml:X>4283473.363317592</gml:X> <gml:Y>5238410.644518324</gml:Y> </gml:coord> <gml:coord> <gml:X>4635323.458982407</gml:X> <gml:Y>5604895.796881676</gml:Y> </gml:coord> </gml:box> </gml:boundedBy> <gml:featureMember> <gml:Point srsName="http://www.opengis.net/gml/srs/epsg.xml#4326"> <gml:coordinates>4468219,5334317</gml:coordinates> </gml:Point> <poi.ID>409</poi.ID> <poi.Name>Stadtgespr</poi.Name> <poi.code>11001</poi.code> <poi.str>Gabelsbergerstr.</poi.str> <poi.Hausnr>38</poi.Hausnr> <poi.Attr>Happy Hour 21:30-22:30</poi.Attr> </poi> </gml:featureMember> </collection> </information> <system> <devicedisplay> <height>320</height> <width>240</width> </devicedisplay> <formats> <supported>SVG</supported> <supported>BMP</supported> </formats> <connection>wlan</connection> </system> </context>

Context information in mobile computing can partly be derived from different sensor information. Schmidt et al. (1998) show in an example of sensor fusion how to derive first symbolic abstractions, termed cues, from physical sensor data and then how to map these

(Schmidt et al., 1998) Schmidt, A., Beigl, M. and Gellersen, H.-W. (1998): There is more to context than location, Proc. International Workshop on Interactive Applications of Mobile Computing (IMC98), Rostock, Nov., 1998


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cues to contexts. Some context information can be accessed from other sources and has not necessarily to be sensed in situ. The Internet and web services which constitute a distributed computing environment allow for the extracting of context information by georeferencing methods. An example is the retrieving of weather conditions for a given location from a mete-orological web service.

For any kind of adaptation, i.e. also the adaptation in a geo-visualisation service based on the mobile usage context, a formalisation of context is essential. So far, only a few attempts to formalise context have been made, e.g. (Boy 1991; Hewagamage and Hirakawa 2000; Hirakawa and Hewagamage 2001; Schmidt and Gellersen 2001). In the most general form situation and con-text can be described as functions of a set of parameters. These parameters are of mixed type and level: some parameters can be numerical, others are per definition symbolic, some parameters are atomic, and others are composed of numerous sub-parameters. Chen and Kotz (2000) distinguish low-level contexts (e.g. location, time, orientation, light level, temperature) and high-level contexts (e.g. current activity).

The situation and context functions can be described as follows: ),(1 tlfS = and RTIAUSfC ),,,,(2=

where: l = location (position as coordinate pair, place name, address) t = time (exact time, time interval, daytime) U = user (identity: uid or user group: gid) A = activities {locating, navigating, searching, identifying, checking} I = information T = system (device capabilities, network type, network bandwidth) R = constraints and rules (valid for the context)

The approach of Hewagamage and Hirakawa (2000) introduces the situation metaphor for modelling human-computer interaction. The context space CS is a set of past usage contexts iC , i = 1, …, ∞:

( )iiiiiii

i TIAUSfCCS ,,,,1

21

∑∑∞

=

∞

=

==

The information that is relevant in a particular context iC can be expressed as a function to retrieve a subset ie of information enti-ties E : ( ) { }EeeCr iii ∈=

Let two distinct contexts iC and jC such that CSCC ji ∈, and the following conditions hold:

If CSCC ji ∈∆ then ε<− ji ll

(Boy, 1991) Boy, G. (1991): Intelligent Assistant Systems: Academic Press

(Hewagamage and Hirakawa, 2000) Hewagamage, K. P. and Hirakawa, M. (2000): Situated Computing: A Para-digm to Enhance the Mobile User's Interaction, in, Handbook of Software Engineering and Knowledge Engineering: World Scientific Publishing Company

(Hirakawa and Hewagamage, 2001) Hirakawa, M. and Hewagamage, K. P. (2001): Situated Computing: A Para-digm for the Mobile User-Interaction with Multimedia Sources, Annals of Software Engineering(12): 213-239

(Schmidt and Gellersen, 2001) Schmidt, A. and Gellersen, H.-W. (2001): Modell, Architektur und Plattform für Informationssysteme mit Kontext-bezug, Informatik Forschung und Entwick-lung(16): 213-224

(Chen and Kotz, 2000) Chen, G. and Kotz, D. (2000): A Survey of Context-Aware Mobile Computing Research, R2000-381, Department of Computer Science, Dartmouth College


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for a given distance threshold 0>ε and ji tt + is a continuous period and where the operator ∆ means the concatenation of two contexts. If CSCC ji ∈∆ then jC is 1+iC

If ( ) Ø=iCr then iC is a null context.

To access elements in the context space, an exploration function F based on the context dimensions can be defined:

( ) ( ) ( ){ }PCPCGCPCF jiji ,,, ⊂=

where { }TIAUtlP ,,,,,∈ and ( )PCG , is a function for getting the values of the specified dimensions P constituting the context.

The model can gradually learn from the user through his/her real world activities and interactions with the mobile system. The for-malism of context described above can be used to capture contexts of usage or usage patterns in mobile cartography. If, for instance, in context Q user W asked for information entities V, this is stored in the context space. In a future usage context, if the context is similar to context Q of the context space, the entity set V could be applied.

Strongly connected to the modelling of the context space is the approach of Schmidt and Gellersen (2001) for determining the validity of context. They argue that the validity of context is dependent on space and time. With increasing spatial or temporal distance from the existence of a context instance the validity is de-creasing. The basic principles for their approach are:

• principle of locality: the relevance of a context is maximal for the location of its origin and is decreasing with in-creasing distance from the origin; after a specified distance from the origin the context has no more rele-vance

• principle of temporality: the relevance of a context is maximal for the time of its origin and is decreasing with increasing temporal distance from the time of origin; after a specified time from the time of origin the context has no more relevance

• principle of independence: the user and producer of con-text are independent; several users or producers of the same context may exist independently

• principle of distribution and scalability: the distribution of information is locally bound (locational scalability); the



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existence of information is temporally bound (temporal scalability)

The temporal aspects of geospatial objects could be modelled according to approaches for spatio-temporal models (Pfoser and Tryfona 1998). The importance of temporal information is stressed by Miller (2003): “… LBS can benefit from the time geographic and activity analysis available through a people-based GIS. One pos-sible benefit is supporting space-time queries. Queries such as ‘Which locations can I reach in 15 minutes?’, ‘Who can attend this event?’ or ‘Can I meet my friends at the pub this evening?’ are in fact queries against space-time prisms. “

Schmidt and Gellersen (2001) propose a concrete context spatio-temporal relevance model using fuzzy set theory. The basic idea of the fuzzy set theory is that the membership of sets is not binary, i.e. crisp, but that with a certain relevance an element belongs to a set. This is determined by a function, the membership function.

A membership function for a normal set S looks like

( ) ∈

=otherwise

Sxxs ,0

,1µ where x is an element, that is x is either a

member of the set S or not. In contrast, the membership function for a fuzzy set A looks like ( ) [ ]1,0A ∈xµ , i.e. x is assigned a value between 0 and 1. Typical membership functions are the triangle or the trapezoid function.

For the temporal relevance it is assumed that the context arises at 0t . Furthermore, the relevance should decreases with further

temporal distance. These distances are mapped to the interval [0,1]. Finally it is assumed that beyond a certain temporal distance ( maxt ) the relevance is zero (Schmidt and Gellersen 2001). Fig. 26 (top) illustrates the following trapezoid membership function (µA) that can be applied to model the temporal relevance:

( )

≤

<<−−

≥

=

min

maxminminmax

max

max

1

0

txif

txtifttxt

txif

xAµ

where mint marks the distance up to that the relevance is 1 and maxt is the distance from which on the relevance is 0.

For the modelling of the spatial relevance a trapezoid member-ship function using the spatial distance sd of the features to the

(Pfoser and Tryfona, 1998) Pfoser, D. and Tryfona, N. (1998): Requirements, Definitions and Notations for Spatiotemporal Application Environ-ments, Technical Report, CH-98-09

(Miller, 2003) Miller, H. (2003): What about People in Geographic Information Science?, in D. Unwin (Ed.), Re-Presenting Geographic Information Systems (in press): John Wiley & Sons


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context origin location is applied (Fig. 26 bottom). The spatial dis-tance is calculated as:

( ) ( )202

00 yyxxlllds −+−=−=∆=

where 0l is the location of the context origin.

At 0l the relevance is maximal, 1, and with increasing spatial dis-tance the relevance decreases constantly up to a maximal distance ( maxd ), from there onwards the relevance is zero.

Fig. 26: Spatial and temporal relevance function (adapted from Schmidt and Gellersen 2001)

A similar approach of fuzzy context modelling is proposed in (Mäntyjärvi and Seppänen 2003). This formalisation helps to de-scribe situations and contexts and allows for finding typical patterns. The parameters above are not all available in explicit form. Position, time, device capabilities, and identity are in most cases available or can be sensed. Activities, rules, and constraints have to be inferred from these parameters in an intelligent way.

Apart from the single context dimensions and their formalisation two ways of structuring context are to be mentioned: scope of context and the levels of context. Similar to mobile activities the


(Mäntyjärvi and Seppänen, 2003) Mäntyjärvi, J. and Seppänen, T. (2003): Adapting applications in handheld devices using fuzzy context information, Interacting with Computers 15(4): 521-538


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context in which these activities take place is dependent on scale. Context can be attributed to different scales (see Fig. 22) and can hence be observed locally, regionally or globally. In that sense scale is essential for detecting context patterns. An example where this kind of spatial context is used is the user interface of GISD, a spa-tial viewer product of the company IONIC. The user interface provides for storing and accessing spatial contexts, i.e. similar to views on the data with different extents and scales. There is also a differentiation in ‘local’ and ‘remote’ contexts. Context for mobile cartography can be understood as composed of distinct layers building a context hierarchy. There is a certain grade from general to more specialised context (see Fig. 27). This allows for starting off with the general context that seems to be easier to model.

Fig. 27: Hierarchical levels of context

The sensing of context, primarily the tracking of locations, rises many privacy concerns, e.g. (Ackerman et al. 2001). Most impor-tant the user must always be informed about the fact that he/she is located and must have the possibility to turn this feature off. How-ever, it should not be forgotten that subscribers of mobile networks are tracked anyway, because the mobile technology relies on the location information. Furthermore, in many circumstances, information about consumers is collected with the knowledge of the people. The connection of such data with location information seems problematic and frightening to many people.

(Ackerman et al., 2001) Ackerman, M., Darrell, T. and Weitzner, D. J. (2001): Privacy in Context, Human-Computer Interaction 16: 167-176


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4.2.4 Information in mobile enviroments

The ‘raw material’ for visualisation in mobile cartography is the geographic information itself. This information can be distributed in different repositories, of different scale, and data types. It can be maps, images, geographic features or other resources. If one has a service concept and mobile devices as target platform in mind, only a flexible information structure can meet the requirements of providing adequate information to the user. The structure of the information is essential for the overall quality of mobile cartogra-phy and a crucial factor for an adaptive geovisualisation. The units of information need to be as atomic or granular as possible. In the case of geographic information this is on the feature level for vector data or on the biggest level of detail for raster data. In the OpenGIS Guide the concept of feature collections is defined (Buehler and McKee 1998, p. 41):

Feature Collections are comprised of Features, the basic unit of digital geospatial information. Features may be defined recur-sively, so there can be considerable variation in feature granularity.

An aggregation, classification or grouping is always possible, whereas the opposite is not. Different approaches to intelligently structuring the information are imaginable. A very pragmatic approach – known from thematic mapping – is to separate core information from additional information, e.g. base map plus dynamic information, i.e. points of interest (POI), routes, etc.

A concise concept of such a procedure is presented in the work of Goel (2001). She distinguishes different layers based on the volatile character of the information. The core layer holds information of more static or permanent nature that is updated in regular periods. For the purpose of this work, this layer would incorporate a base map and further thematic layers such as public transport network. The service layer consists of information layers representing more dynamic and volatile information that can be retrieved real-time from a central server. The service layer acts as a linking structure between the referential objects and related services. A similar approach is taken by Jung and McKeown (2001). They give an example of a conference map consisting of a static part showing the architectural layout of the conference and dynamic parts that can be modified according to quantitative and qualitative changes.

Another classic work is Lynch’s attempt to describe the structure of cities (Lynch 1960). He identified five structural elements forming the image of a city: paths, edges, districts, nodes, and

(Buehler and McKee, 1998) Buehler, K. and McKee, L. (1998): The OpenGIS® Guide: Introduction to Interoperable Geoprocessing and the OpenGIS Specification, 3rd Edition, OGC Technical Committee of the Open GIS Consortium, Wayland (MA)

(Goel, 2001) Goel, A. (2001): URBAN PILOT - A Dynamic Mapping Tool for Personalizing the City through Collective Memory, Master's Thesis, Department of Architec-ture, Massachusetts Institute of Technology

(Jung and McKeown, 2001) Jung, B. and McKeown, J. (2001): Adaptive Graphics, Proceedings XML2001, Orlando (FL)

(Lynch, 1960) Lynch, K. (1960): The Image of the City, Cambridge (MA): MIT Press & Harvard University Press


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landmarks. These elements are important for the building of men-tal maps as well as physical maps. Lynch’s work offers useful concepts for structuring information, but also for the extraction of structural information to be included in a map.

The most common information type in LBS are points of interest (POI). However, it will become necessary to model other informa-tion types as well, such as regions of interest (ROI), time (point) of interest (TOI) or time intervals of interest (TIOI). For this purpose geographic information has to be modelled spatio-temporally on the most atomic level. Regarding space only, this implies the usage of simple features. OGC has defined standards, such as the Simple Feature Specification and the Web Feature Server (WFS). In antici-pation of the implementation, it has to be said that a WFS typically delivers feature data in the form of GML. The separation of model and view as visualised in Fig. 20 can be found in the use of GML as the modelling language of geographic information, the geographic model, and SVG as the presentation format or presentation model. Above all this differentiation is congruent with cartographic model theory. In this theory a primary model is distinguished from a sec-ondary, derived model that is perceived by the user and consequently constitutes his/her mental model, the tertiary model (see Fig. 28).

Fig. 28: Geographic information modelling

The framework shown in Fig. 20 also contains another kind of information that is only implicitly indicated with the context frame. It is information belonging to context as discussed above. This type of information has to be distinguished from the informa-tion to be displayed. The information belonging to context could be sensorial information, co-located objects or constraints of the context. Fig. 29 illustrates the relationship of reality, sensorial information, and modelled information of the real world.


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Geographic information is a subset of reality modelled for dif-ferent purposes. The sensorial information of the user perceived in the current geographic information usage context is also a subset of reality, but also partly of the geographic information as a model of reality. This knowledge about the user’s surroundings is an im-portant part of the context.

Fig. 29: Relationship of information types

In the last few years a lot attention in the geographic information science has been drawn to ontology. An ontology is according to Gruber (2001) “… an explicit specification of a conceptualization”, or studies according to Smith (2001, p. 592f.) “… the totality of objects, properties, processes and relations which make up the world on different levels of focus and granularity …“. The specifi-cation involves the determination of a standardised taxonomy of objects in a domain. For the geographic information most recently research on geo-ontologies has been undertaken. Geo-ontologies can be understood to provide semantic references for geographic information (Kuhn 2001; Kuhn 2002). It is not the purpose of this thesis to cover ontology, but the development in this field is cer-tainly of major importance for mobile cartography. Ontologies might help to model the information dimension of context in the sense discussed above.

Another important aspect of information is its quality. The qual-ity of geographic information may vary substantially. In the case of mobile geographic information usage where the user receives geo-graphic information from different content providers and has to make quick decisions the meta-information about quality is crucial. This information quality affects different dimensions in mobile cartography: it could simply be the accuracy of the position, the completeness or timeliness of the geographic information or it could affect the attributes of geospatial objects, for instance their currency. Another aspect discussed further below is the relevance of the information. In mobile environments the chance for inferior data quality is quite big. Duckham et al. (2002, p. 89) coin the term imperfection which comprises the two orthogonal concepts error

(Gruber, 2001) Gruber, T. (2001): What is an ontology? http://www-ksl.stanford.edu/kst/what-is-anontology.html

(Smith, 2001) Smith, B. (2001): Geographical catego-ries: an ontological investigation, International Journal Geographical Information Science 15(7): 591-612

(Kuhn, 2001) Kuhn, W. (2001): Ontologies in support of activities in geographical space, International Journal Geographical Information Science 15(7): 613-631

(Kuhn, 2002) Kuhn, W. (2002): Geo-Ontologies for Semantic Interoperability, Proceedings, Ilkley, UK, September 16, 2002.

Duckham et al., 2002) Duckham, M., Mason, K., Stell, J. and Worboys, M. (2002): A Formal Approach to Imperfection in Geographic Information, Computer, Environment and Urban Systems 25: 89-103


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and imprecision, where error (or inaccuracy) designates a lack of correlation of an observation with reality and imprecision concerns a lack of specificity in representation. They further state that the concept of granularity that has been mentioned above is closely related to imprecision. They define granulation as “… the result of distinct entities becoming indiscernible due to the imprecision in an observation” (ibid., p. 90). Generally, granularity can be under-stood as the smallest unit (or grains) of information that can be measured or distinguished respectively. Within such a grain, information differences are indiscernible. Thus, coarse granularity results in less detail. These facts have two consequences: first, the mobile user should have access to any kind of data quality infor-mation as much as possible. Second, the granularity of information is an important factor for the degree of adaptation that is possible.

Information demand or spatial questions have been introduced in section 4.2.1 (see Fig. 21). A rather extreme view in the geo-graphic information and cartography community is that in principle all spatially related goals or information demands are reducible to the two basic questions: where is that? and what is there? The problem of this reduction is that the spatial appearance of certain phenomena or objects can depend on time. Therefore at least the question when? is needed as well. This view can for instance be found in a discussion of map meaning. MacEachren (1995, p. 312) speaks of a “… space, time, attribute taxonomy of denotative meaning in maps. Maps are about things at particular places and times. The interpretants of map signs (or maps as signs) include not only interpretation of ‘what’ the sign means but of ‘where’ and ‘when’ the meaning holds”. The approach of Mennis et al. (2000) is along the same lines describing three different cogni-tive systems, the what, where, and when system. They are separate, but there is a strong interdependency between the what and where. The basic question types thus focus either on the where (location), what (geospatial object, person, activity) or when (time).

• where: who (person) | what (object, activity) | when (time); for example: where is Maria and what is she doing now?

• what: what (object, attribute, activity) | when (time); for example: what can you do in X on a Sunday?

• when: who (person) | what (object, attribute, activity); for example: when is shop A open?

Mennis et al., 2000) Mennis, J. L., Peuquet, D. J. and Qian, L. (2000): A Conceptual Framework For Incorporating Cognitive Principles Into Geographic Database Representation

MacEachren, 1995) MacEachren, A. M. (1995): How maps work: representation, visualization, and design, New York (NY): Guilford Press


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Fig. 30: Question and answer model (adapted from Heidmann 1999, p. 97)

A similar approach is taken by the WebPark project, where a model of questions is differentiated from a model of answers (Edwardes et al. 2003b). The question model separates five ques-tion types that are very similar to the questions related to the elementary user actions (see Table 7): Presence, Distribution, Con-firmation, Identification, and Association. Lee et al. (2002) give a somewhat different classification of query types in LBS based on two dimensions. The first is the spatial scope of the query. Local queries are associated to the user’s current location. Non-local queries relate to any other location. The other dimension regards the complexity of the query. Simple queries are based on simple attribute conditions. General queries are formed by more complex conditions either spatially-constrained or non-spatially con-strained. The spatially constrained queries involve common GIS operations such as intersect, contain, contained_by, within_distance etc.

The main goal of any geoservice – and a geovisualisation service is no exception – is to give answers to these users’ questions related to space and time. Or to put it differently, the service will provide solutions to mobile users’ spatial problems by meeting the infor-mation needs. The information demand can be explicit or implicit. An explicit information demand is expressed in the form of queries or natural language questions. The long term goal is that a system recognises implicit information demands of a user and transforms them to explicit queries. This step would require the capability of the system to infer beliefs about users’ goals or intentions. This is a very difficult, maybe an impossible task. In (Horvitz 1999) this aspect is described for the user interface domain. So far, the user has to take the initiative and make his/her information demands expressive to the system by forming queries. These queries can trigger an adaptation. Hence, this is a state between an interactive system where the user has to do all adaptations and configura-


(Edwardes et al., 2003b) Edwardes, A., Burghardt, D. and Weibel, R. (2003b): WebPark - Location Based Services for Species Search in Recreation Area, Proceedings 21st International Cartographic Conference, Durban, South Africa, August 10-16, 2003

(Lee et al., 2002) Lee, D. L., Xu, J., Zheng, B. and Lee, W.-C. (2002): Data Management in Loca-tion-Dependent Information Services, pervasive computing(July-September): 65-72

(Horvitz, 1999) Horvitz, E. (1999): Principles of Mixed-Initiative User Interfaces, Proceedings ACM SIGCHI Conference on Human Factors in Computing Systems, Pittsburgh (PA), May, 1999, ACM Press. http://citeseer.nj.nec.com/ horvitz99principles.html


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tions, and a fully adaptive system that would recognise the user’s information demands and react to them correspondingly.

The role of adaptation in the context of a mobile geovisualisation service is to assure adequate information or an adequate answer to the user’s problem. Adequacy is a quality measure, namely fitness for use. If the information is useful in a current usage context and to an individual user, if it is adequate in amount and form, it is valuable and hence of high quality. However, not only the infor-mation content must be adequate, but also the information presentation form has to be adequate. Depending on the usage context and the information content of the answer, a map might not be the adequate presentation form.

Information as described above is related to what, where, and when. In the mobile cartography framework, the main task is to select and maybe filter the relevant information for the current usage context. In what way the selected information is presented is the topic of section 4.2.6, where different visualisation principles and techniques suitable for mobile cartography are discussed. Raper et al. (2002, p. 44) take a similar view by stating that “ … understanding the individual ‘geographical relevance’ of infor-mation will be necessary for location-based services to provide appropriate information and identifies movement patterns, spatio-temporal constraints, geographical associations and setting as the key components”. The relevance of geographic information is dependent on the user’s geography. For a personal geography (egocentric) the relevance is mainly influenced by the current activity and for a more detached geography such as an overview (allocentric) the relevance can be determined through an analysis of geographic information retrieval tasks (Raper et al. 2002).

Relevance is also the central issue in adapting to mobile geo-graphic information users. The relevance of information is strongly dependent on the usage context and its dimensions as described in section 4.2.3. Like context relevance is a fuzzy concept. A general introduction to relevance in information retrieval is provided by Borlund (2003). Relevance has to do with information needs, infor-mation seeking, and information use. Different models and theories about information needs and relevance have been pro-posed from different disciplines. In information retrieval (IR) the objective is to “ … retrieve all the relevant documents [and] at the same retrieving as few of the non-relevant documents as possible” (van Rijsbergen 1979, p. 6). This can be applied as well to geo-graphic information retrieval and also to its presentation in maps.

(Raper et al., 2002) Raper, J., Dykes, J., Wood, J., Mountain, D., Krause, A. and Rhind, D. (2002): A framework for evaluating geographical information, Journal of information science 28(2): 39-50

(Borlund, 2003) Borlund, P. (2003): The Concept of Relevance in IR, Journal of the American Society for Information Science and Technology 54(10): 913-925

(van Rijsbergen, 1979) van Rijsbergen, C. J. (1979): Information Retrieval, London: Butterworths


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A very early and broad definition of relevance is given by Rees (1966) in (Greisdorf 2000, p. 67):

the criterion used to quantify the phenomenon involved when individuals (users) judge the relationship, utility, importance, degree of match, fit, proximity, appropriateness, closeness, perti-nence, value or bearing of documents or document representations to an information requirement, need, question statement, description of research, treatment, etc.

Pertinence is often used as a synonym for relevance and refers to items that satisfy the user’s information needs and build the user satisfaction. In cognitive science the term salience is used to denote a similar concept.

A very broad and general framework for explaining information needs has been developed by Dervin (1983). This meta-theoretic approach termed sense-making theory comprises four constitu-ents: a situation in space and time defining the context in which information needs arise, a gap that represents the difference between the actual and the desired situation, an outcome, i.e. the result of the sense-making process, and a bridge that stands for any means closing the gap between situation and outcome. The basic idea of sense-making theory can be illustrated with the sense-making triangle (see Fig. 31): “The situation provides the context in which the individual needs to make sense of something (gap) that forces him to seek for help” (Kari 1998). According to Dervin, the need for information arises from a gap in our cognition of the world and thus information could help us to make sense of the world by filling these gaps.

Fig. 31: The sense-making triangle

Gershman et al. (1999, p. 3f.) argue that the most important task in situated computing is to bridge the gap between user intentions and the possible actions to achieve them and propose three types of discontinuities: physical, informational, and awareness. A physical discontinuity arises, if one is not in a place where an

(Greisdorf, 2000) Greisdorf, H. (2000): Relevance: An Interdisciplinary and Information Science Perspective, Informing Science 3(2): 67-71

(Dervin, 1983) Dervin, B. (1983): An overview of sense-making research: concepts, methods, and results to date, Proceedings Interna-tional Communication Association Annual Meeting, Dallas (TX), May 1983

(Kari, 1998) Kari, J. (1998): Making Sense of Sense-Making: From metatheory to substantive theory in the context of paranormal information seeking, Proceedings Nordis-Net workshop (Meta)theoretical stands in studying library and information institu-tions: individual, organizational and societal aspects, Oslo, Norway, November 12–15, 1998

(Gershman et al., 1999) Gershman, A. V., McCarthy, J. F. and Fano, A. E. (1999): Situated Computing: Bridging the Gap between Intention and Action, Proceedings 3rd International Symposium on Wearable Computers, San Francisco (CA), October 18 - 19, 1999, 3-9


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effective action can be taken. If one knows what to do, but the information necessary to actually perform the action is not available or accessible, this is called an information discontinuity. Finally, an awareness discontinuity happens, if through situational constraints one fails to become aware of present opportunities to achieve a goal. Among other prototypes helping to overcome these gaps, the authors propose an ActiveMap tool. This tool supports the awareness of people acting within the physical environment by representing the locations of co-workers and the freshness of the location information.

The information seeking process can generally be divided in active and passive seeking, for example searching and browsing. There are several measures to determine the efficiency and effec-tiveness of search or retrieval processes. The most common group of measures is based on a binary notion of relevance, i.e. a docu-ment is either relevant or it is not. Based on the binary relevance several measures can be defined. Precision is the ratio between the number of retrieved and relevant and the total number of retrieved documents. Recall is the ratio between the number of retrieved and relevant and the possible relevant documents. A step further is the introduction of ranks for the retrieved documents based on the similarity of the document and the query. Instead of binary, con-tinuous relevance can be used (Mizzaro 2001).

Two different concepts of relevance are distinguished in litera-ture, e.g. (Saracevic 1996): the system or objective relevance and the user or subjective relevance. In the first case it is assumed that there is an algorithmically measurable objective relevance. In the latter cases the presumption is that only the user can judge the suitability of the retrieved information. Based on these two classes several types of relevance can be identified. The typification is based on the relations of (retrieved) objects and queries, requests, information needs or the underlying situation that triggers the need for information (Borlund 2003). The five relevance types pro-posed by Saracevic (1996) are:

Objective relevance • System or algorithmic relevance: this relevance type is

independent of the context and measures how well the query topic and document topic match.

Subjective relevance • Topical-like relevance: aboutness, topicality • Pertinence or cognitive relevance • Situational relevance

(Mizzaro, 2001) Mizzaro, S. (2001): A New Measure Of Retrieval Effectiveness (Or: What's Wrong With Precision And Recall), in T. Ojala (Ed.), International Workshop on Infor-mation Retrieval (IR'2001), Infotech Oulu, Oulu, Finland, September 19-21, 2001, 43-52

(Saracevic, 1996) Saracevic, T. (1996): Relevance recon-sidered, Proceedings Second Conference on Conceptions of Library and Informa-tion Science (CoLIS 2), Copenhagen

(Borlund, 2003) Borlund, P. (2003): The Concept of Relevance in IR, Journal of the American Society for Information Science and Technology 54(10): 913-925


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• Motivational and affective relevance The concept of subjective relevance assumes that the relevance of

information can only be determined in use. This view is reflected by the situational relevance covering the contextual factors of information relevance. Although the spatio-temporal aspect of relevance that is of major importance in mobile cartography could be subsumed under this situational relevance, it is reasonable to express the spatial relevance and temporal relevance (timeliness) explicitly.

Keim and Kriegel (1994) propose an approach for calculating a relevance factor. The method first determines for each feature the distance between the attribute values and the corresponding query values. The distance functions used depend on the data types. For non-metric data types the authors suggest the use of domain-specific distance functions or a distance matrix. The next step combines the independently calculated distances for the selection predicates. Since the relative importance of the selection predicates must be considered, weighting factors for each of them have to be defined. The distances may also vary in magnitude and thus need to be normalised. Finally the normalised values are combined into a single distance value by applying a numerical mean function.

Geographic or spatial relevance can consider the current position and the Euclidean distances to the retrieved features and thus de-termine the relevance factor. Temporal relevance can be calculated using time differences. For a simple example it is assumed that the user has an information need for events in his/her neighbourhood. That means the user poses a query and the service will return fea-tures (events) relevant to the user in his/her usage situation. The event with the highest relevance to the user is assumed to be the one that is closest to the user’s position, will begin next in time or has started last, and matches the topical interest best. The spatial, temporal, and topical relevance can be measured according to the method described above. The overall relevance is a combination of spatial, temporal and topical relevance. Table 9 shows the event data for the example calculations.

id name x y category date time event type

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Staatstheater am Gaertner-platz 520.09 661.59 56009 23102003 1930 opera

261 Werkstattkino 313.33 627.67 56010 23102003 2015 studio movie

262 Theater am Frauenhofer 306.66 633.10 56009 23102003 2000 comedy

496 Arena 107.98 521.81 56010 23102003 1845 action movie

565 Marionetten- 113.46 755.75 56009 23102003 1530 children

(Keim and Kriegel, 1994) Keim, D. A. and Kriegel, H.-P. (1994): VisDB: Database Exploration Using Multidimensional Visualization, Com-puter Graphics & Applications Journal 14(5): 40--49


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theater play

757 VOLLMER Haus Theater 058.65 985.14 56009 23102003 2100

classic play

1185 Maxx 1004.59 997.41 56010 23102003 2045 action movie

1305 Imax 1266.91 694.81 56010 23102003 1700 nature movie

1306 Planetarium 1280.05 682.87 56010 23102003 1730 nature movie

Table 9: Sample event table

The user’s position ( )UUU yxP , is: 340.00, 925.00 and the current time ct is 19:00. Fig. 32 shows the spatial distribution of the events and the user’s position in relation to the events. Furthermore, the minimal and maximal distance between the user’s position and the events is depicted. The user’s query encompasses all events for the category cinema and the event type ‘action movie’.

Fig. 32: An example of event relevance

The spatial distance sd is calculated with the following function:

( ) ( ) ( )22ueueueis yyxxllled −+−=−=∆=

where events ( )nei ,,1 K= and locations ( )ii yxl ,

The temporal distance td is calculated with the following function:

( ) ( )( ) ( )cececeit mimihourhourttted −+−=−=∆= 60*

where events et is the time of the event and ct is the current time of usage; mi are the minutes of the respective times. The topical distance is calculated with the following function:

( )

=

=∧=

=∧≠

≠∧≠

querycategorycategoryqueryeventtypeeventtypeif



itop ed

1

5.0

0


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The spatial and temporal distances are normalised using the fol-lowing function: ( ) ( ) iniinorm ddded ,min K=

The total relevance is: ( ) toptnormsnormitot ddderel ,,∑= and normalised with: ( ) ( ) ( ) ( )( )ntotitotitotinormtot erelerelerelerel ,,max_ K=

The resulting distances and relevance values are illustrated in the table below (Table 10). Although event 496 is not the nearest event, it is the most relevant, because it has the highest topical and tem-poral relevance values.

id name ds dt dtop dsnorm dtnorm reltot reltot_norm reltot %

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Staatstheater am Gaertnerplatz 319.09 30 0 0.89 0.50 1.39 0.53 53.2

261 Werkstattkino 298.52 75 0.5 0.95 0.20 1.65 0.63 63.2

262 Theater am Fraunhofer 293.80 60 0 0.96 0.25 1.21 0.46 46.5

496 Arena 465.18 15 1 0.61 1.00 2.61 1.00 100.0

565 Marionetten-theater 282.78 210 0 1.00 0.07 1.07 0.41 41.1

757 VOLLMER Haus Theater 287.71 120 0 0.98 0.13 1.11 0.42 42.5

1185 Maxx 668.52 105 1 0.42 0.14 1.57 0.60 60.0 1305 Imax 955.07 120 0.5 0.30 0.13 0.92 0.35 35.3 1306 Planetarium 970.73 90 0.5 0.29 0.17 0.96 0.37 36.7

Table 10: Relevance results for event query

4.2.5 User interfaces and mobile geovisualisation

The user interface in mobile cartography is tightly connected with the general problems of mobile system interfaces. In chapter 2 these problems have been discussed. The interactivity of a mobile map interface will certainly be more limited compared to other digital map interfaces. Even though, as stated in the last section, a map is not always the right answer form, it still can act as a user interface to further information, especially in mobile environments. Clicking, pointing, etc. is much easier and more error free than other input mechanisms. A map interface can for instance ease the complications of textual queries for other applications. 4.2.6 Visualisation in mobile cartography

The visualisation in a mobile context raises many requirements associated with graphics and generalisation. In many ways the visualisation of mobile maps is related to on-demand mapping.


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On-demand maps are defined by Crampton (1999) as “maps created at the moment of need by the user”. Cecconi (2003) argues that the primary characteristic of on-demand mapping is that the user specifies the moment (on-demand) and manner of map pro-duction. If on-demand mapping happens in real-time, it relies on on-the-fly generalisation which he defines as “the creation of a cartographic product upon a user request appropriate to its scale and purpose” (ibid., p.3). In addition to this definition he gives a set of characteristics of on-demand maps:

• temporarily generated dataset at reduced scale for visualisation

• dataset matches user preferences and display specifica-tions

• scale and map content not pre-determined • dataset generated automatically without visual control

before publishing • dataset must arrive on the display in a user specified time

slot

These definitions are valuable for mobile cartography as well. However, as explained in section 4.1, mobile maps go even further. Apart from purely visualising geographic information, geographic information that is adapted to the usage context and the context itself become the subject of visualisation. This involves visualising information quality (e.g. the current position within a certain toler-ance range), the availability and accessibility of objects, the relevance of objects, dynamic information, temporal information, validity and certainty of information, etc. The semantics of geo-spatial objects are dependent on context. Thus, there should be much care on visualising these semantics in mobile cartography where the context is due to change by nature.

The demands on visualisation are enormous. At the same time the restrictions are very severe, as mobile users have high expecta-tions. Visualisation on mobile devices should be simple, focussed, clear, and easily legible. The visualisation must fit into the current usage situation, i.e. it has to provide personalised content and the presentation must be adapted. The visualised geographic informa-tion needs to be up-to date, accurate, and well conceivable. Furthermore this information must be linkable to other information, i.e. compatible with other services. Moreover, the visualisation should reflect the dynamic changes in the environ-ment and provide information on-demand. Finally, the visuali-

(Crampton, 1999) Crampton, J. W. (1999): Online Map-ping: Theoretical Context and Practical Applications, in W. Cartwright, M. P. Peterson and G. F. Gartner (Eds.), Multimedia cartography, Berlin; Heidel-berg; New York: Springer-Verlag



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sation has also to arrive quickly on the mobile device and must be rendered fast.

From the elementary user actions listed in Table 7 and the requirements stated above a minimal set of functions mobile maps should offer can be derived. Mobile maps must be able to visualise at least the following: locations and routes, POIs and ROIs, entities (qualitative and quantitative distinctions), search results (objects, distances, relationships, relevance, importance, availability, time criticality etc.), events, multimedia information (images, text, sound etc.), relevance or importance as a visual ranking, spatial relationships (rather topological than metrics) and spatial patterns and distributions.

Cartography has a rich toolbox at its disposal for accomplishing the task of designing maps that work for the mobile usage context. First, there are general design principles and design methods. And second, there are design guidelines stating when and how to use these methods and which parameter values are to be set.

Different visual design principles are available, which are well examined and documented in graphic design literature (see for example Ware 1999; Mullet and Sano 1995):

• Gestalt Theory (Koffka 1935): This theory proposes dif-ferent design principles based on human visual perception: proximity, similarity, continuity, symmetry, closure, relative size, figure and ground.

• conciseness (Prägnanz): this concept was proposed by Bertin (1974, p.17): Die Prägnanz wird wie folgt definiert: Wenn eine Konstruktion zur richtigen und vollständigen Beant-wortung einer gestellten Frage unter sonst gleichen Voraussetzungen eine kürzere Betrachtungszeit erfordert als eine andere Konstruktion, so bezeichne man diese als prägnanter in be-zug auf die gestellte Frage. … Die Prägnanz ist gleichbedeutend mit einem Minimum an geistigem Aufwand des Lesers bei jeder Stufe des Leseprozesses einer Zeichnung.

• clarity: This design principle has two notions. The first refers to the general tidiness of a map. The second means a special graphical variable introduced by MacEachren (1995, p. 275f.): “The three visual variables (or subdivi-sions of clarity) are crispness, resolution, and transparency.”

• visual contrast: the map elements should be different enough

(Ware, 1999) Ware, C. (1999): Information visualiza-tion: perception for design, San Francisco: Morgan Kaufman

(Mullet and Sano, 1995) Mullet, K. and Sano, D. (1995): Designing Visual Interfaces - Communication Oriented Techniques, Englewood Cliffs (NJ): Sunsoft Press - Prentice Hall

(Koffka, 1935) Koffka, K. (1935): Principles of Gestalt Psychology, New York (NY): Harcourt-Brace

(Bertin, 1974) Bertin, J. (1974): Graphische Semi-ologie, Berlin: de Gruyter

(MacEachren, 1995) MacEachren, A. M. (1995): How maps work: representation, visualization, and design, New York (NY): Guilford Press


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• order, grouping, unity: the symbology should reflect a semantic order and grouping.

• harmony: colours, size, forms etc. should be stepped in a harmonic way forming harmonic symbol sets

• structure & balance: the map elements should show a structure

• focus & emphasis: the important features need to be in focus

• visual hierarchy: based on contrast and focus, the impor-tant elements need to lie in the foreground, whereas less important features should be in the background

Several authors have proposed design guidelines for screen maps based on these general design principles, cartographic knowledge, physical and technical conditions, and partly empirical studies. Although all these are targeted at screen maps for static displays, they can in parts be adopted to mobile device displays.

The most comprehensive work has been done by Neudeck (2001).The predominant suggestion is the enforced usage of colour in screen maps. The main reason for this are the problems arising with other traditional design elements (e.g. contours for road sig-natures) on screens due to the raster technology (Neudeck 2001; Brunner 2001). Most of these design techniques stem from the times when copperplate engraving was used in mapmaking and fine graphics were common. These fine graphics, along with rounded graphic primitives (e.g. circles), oblique lines, and serif fonts should be avoided if ever possible. Map text should run hori-zontally. A sufficient contrast between different map elements is necessary, especially when considering the changing light condi-tions of different usage contexts. Furthermore, the minimal dimensions of graphic elements must be increased drastically, both concerning the size of and distances between elements.

Whereas these guidelines are helpful to properly set low level pa-rameters, they cannot help in choosing the appropriate visualisation methods for the context at hand. The work from Zhou and Feiner (1998) heads in this direction. The visual tasks (see Fig. 33) are midlevel components that link the high level pres-entation intents to the low level visual acts.

(Neudeck, 2001) Neudeck, S. (2001): Zur Gestaltung topografischer Karten für die Bildschirm-visualisierung, Dissertation, Schriftenreihe, Heft 74, Institut für Photo-grammetrie und Kartographie, Studiengang Geodäsie und Geoinformation Universität der Bundeswehr München

(Brunner, 2001) Brunner, K. (2001): Kartengestaltung für elektronische Bildanzeigen, in, Karto-graphische Bausteine, Band 19, Dresden: Technische Universität Dresden, Institut für Kartographie

(Zhou and Feiner, 1998) Zhou, M. X. and Feiner, S. K. (1998): Visual Task Characterization for Auto-mated Visual Discourse Synthesis, Proceedings CHI'98, Los Angeles (CA), April 18-23, 1998


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Fig. 33: Visual task taxonomy (after Zhou and Feiner 1998)

Although it is significant to consider the basic cartographic de-sign principles and methods, not all traditional methods are feasible or appropriate anymore (e.g. contours for road signatures etc.). Therefore it is important to integrate also new approaches and strengthening existing means (colour, opacity, animation, etc.). One such interesting idea is to bring more depth into the visualisa-tions. Depth Cue Theory (Ware 1999) offers means such as perspective cues, occlusion, depth of focus, and cast shadows to produce depth impressions. A good example of depth impression in mobile maps is the map shown in Fig. 16. The slightly skewed map together with the silhouettes of major buildings gives a good spatial depth feeling.

One effect of the very small displays in mobile cartography is the focus-context problem: “If we think of the problem of wayfinding as one of discovering specific objects or locations in a larger land-scape, the focus-context problem is simply a generalization of this, the problem of finding detail in a larger context” (Ware 1999, p. 274ff.). Variable-scale maps are one solution to the focus-context problem. Though not the topic of this work, it is important to stress the potential of multimodal user interfaces for providing solutions to the focus-context problem. Apart from relaxing the space prob-lem of the small mobile displays, there are usage situations in which an alternative modality is more appropriate than the visual. In car navigation systems the use of the audio channel is the better solution. Furthermore, the use of more output channels trans-

(Ware, 1999) Ware, C. (1999): Information visualiza-tion: perception for design, San Francisco: Morgan Kaufman


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porting redundant information could help to improve the overall efficiency. Developments of interoperable speech technologies like the Speech Applications Language Tags (SALT) are interesting options for the future. For an introduction to multimodal user in-terfaces for mobile devices see for example (Ringland and Scahill 2003; Oviatt et al. 2000).

Another issue coming up in designing maps for mobile devices are emotions. Norman (2002) describes in his article how design affects emotions. The affective system judges the environment, attributing positive or negative valences. The cognitive system is interprets the world and trying to make sense. The two systems influence each other. He states “attractive things work better”, but concludes that “good design means that beauty and usability are in balance” and further “the products must be affordable, func-tional, and pleasurable – and, above all, a pleasure to own, a pleasure to use”. Along the same lines is the model of Burmester et al. (2003), splitting the overall product quality in a pragmatic qual-ity and a hedonistic quality. Especially for marketing a product or service the hedonistic quality or ‘joy of use’ is of equal importance as the pragmatic quality. Although for the scope of this work information communication (simple but clearly designed) is important, a more ludic presentation is imaginable for many ser-vices. Especially for marketing reasons the entertainment component of services is becoming more and more important. 4.2.7 Technology in mobile cartography

There are a lot of technical issues involved in mobile cartography. Many of them are already known from information technology, telecommunication, and web mapping. In mobile cartography technology plays two very different, almost contradictory roles:

• enabling function: e.g. mobile devices, mobile Internet • restricting function: e.g. small display size, processing

power and memory, bandwidth, etc. This research concentrates on developing methods using the

enabling functions of technology without addressing the restrict-ing factors in detail, because there is reason to hope that some of these will vanish over time and the developed methods will be ready to use then. Several GI functions common in any commercial GIS count to the enabling functions. Acting as the main ‘back-ground’ technology these functions are for instance overlay, point-in-polygon test, proximity analysis, buffers, length, perimeter, or area calculations. Other functions have been described in section 2.2.2 in regard to location based services.

(Norman, 2002) Norman, D. A. (2002): Emotion and Design: Attractive things work better, interactions(july + august): 36-42

(Burmester et al., 2003) Burmester, M., Hassenzahl, M. and Koller, F. (2003). "Usability ist nicht alles - Wege zu attraktiven Produkten." i-com Zeitschrift für interaktive und kooperative Medien(1): 32-40, 2002

SALT: www.saltforum.org/downloads/SALT TechnicalWhitePaper.pdf

(Ringland and Scahill, 2003) Ringland, S. and Scahill, F. (2003): Multimodality — the future of the wireless user interface, BT Technology Journal 21(3): 181-191

(Oviatt et al., 2000) Oviatt, S., Cohen, P., Wu, L., Vergo, J., Duncan, L., Suhm, B., Bers, J., Holzman, T., Winograd, T., Landay, J., Larson, J. and Ferro, D. (2000): Designing the User Interface for Multimodal Speech and Pen-Based Gesture Applications: State-of-the-Art Systems and Future Research Directions, Human-Computer Interaction 15: 263–322


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4.2.8 Summary

This chapter has introduced a new and comprehensive framework for a mobile cartography. The one-sidedness of most existing approaches and solutions together with a too technology oriented approach mainly in the field of LBS have not yielded appropriate solutions. With this framework a more holistic view of the problem of visualising geographic information on mobile devices has been established. The single aspects of mobile cartography have been examined in depth. However, they are all related to each other.

The central element of the framework is context, because it offers a frame for all the other elements. The user performs his/her activities within a context. Through this activity context a dependence of other elements grows, namely the mobility, infor-mation, technology and visualisation.

For the domain of mobile cartography location is the most im-portant element connecting all the others. The user is located, other geospatial objects are located around this location, the activity takes place, technical infrastructure is bound to a location, and the object of visualisation is the location. The matter of scope and scale is connected to this location.

Knowing the context of usage is a prerequisite for adapting the geovisualisation, and of all the context elements the most impor-tant one for adaptation is the user activity. It is also the most difficult one to gather.

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Chapter 5

5 Adaptive visualisation of geographic information

“Point the remote control at the video recorder.’ V. easy. ‘Turn to Index.’ Aargh, horror list with ‘Timer controlled simultaneous HiFi sound recordings’, ‘the decoder needed for encoded programmes’, etc. Merely wish to record Penny Husbands-Bosworth’s rant, not spend all evening reading treatise on spy-ing techniques.” – Helen Fielding, “Bridget Jones’s Diary”

5.1 Transfer of the adaptation concept to geo-graphic information visualisation

The adaptation concept described in its general form in chapter 2 can be transferred to the cartographic domain. Although adapta-tion methods can principally be applied to geovisualisation in general, the major benefits are expected in the mobile domain. The adaptation of mobile geovisualisation is covered in section 5.4 pre-ceded by a discussion of the general concepts and the process of adaptation in the cartographic domain and a study of the relation-ship between generalisation and adaptation.

As it is the case with adaptive hypermedia and adaptive user interfaces, the goal of introducing adaptation mechanisms into cartography is to help users to employ geographic information more efficiently (usability), fitting the presentation to their needs and the limited resources (small display), and enhancing the over-all relevance. The result of adaptation in this setting is an adaptive map that can be defined here as a map or map-like visualisation adapted to a significant extent autonomously by a system or ser-vice. Although the long-term objective is to provide users adaptive maps or geovisualisation that – if at all – only requires marginal adjustments, a few basic principles need to be adhered:


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• the adaptation has to be transparent, i.e. the user needs to know that adaptation takes place and it should be when-ever possible in the form of suggestions

• the user will always have the overall control, i.e. the user can decide whether he/she wants adaptation at all or at certain stages

• the adaptation needs also to be adaptable, i.e. the user can always change – if desired – the geovisualisation by him-self and to the same amount as the adaptive behaviour of the system

Adaptation affects the idea of interactive systems. Interactions are certainly essential for initiating questions or information de-mands. However, adaptive behaviour should minimise interactions and on the one hand they should be reduced to the very essential and necessary ones, on the other hand interactions themselves could be adapted in the sense of aggregating or ab-stracting interactive functions, as well as changing style or structure of interactions. A well known example is the distinction into two major user roles: the novice and the expert. The overall system functionality is the same for both, but some functions could be hidden or aggregated to a more coarse function with fewer parameters for a novice user.

5.2 Adaptation dimensions in geographic infor-mation visualisation If adaptation is studied in cartography, different domains that are affected have to be separated. The following four domains can be identified (Fig. 34):

1) information domain: the information content is adapted to the current situation, user, activities, and system in use

2) user interface domain: the user interface is adapted to the current situation, user, activities, system in use, physical conditions, and mobility (medium and mode)

3) presentation domain: the visualisation of the information will be adapted to the situation, user, activities, co-located objects, system in use, physical conditions and mobility

4) technology domain: the information encoding is adapted to specific devices with different characteristics (display size and resolution, memory, processing power, etc.) or to the transmission media (e.g. network bandwidth)


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view

visualisation

control

user interface

user

activities

adaptation

model

information

context

target

objects

technology technology

Fig. 34: Domains of adaptation

Basically these domains correspond to the major categories in mobile cartography that can be adapted. They will be explained further in section 5.2.2. As explained earlier, the technological domain is only of secondary interest for this work. Moreover, the user interface domain is only very briefly covered, since the dis-cussing of adapting map user interfaces would overstretch the extent of this research.

Fig. 35: Dimensions of adaptation in mobile cartography


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Fig. 35 shows the various dimensions of adaptation (Brusilovsky 1996) in geovisualisation (the numbers in the figure refer to the sections of this chapter where the dimensions are discussed in further detail):

• why: the reasons for adapting geovisualisation have been mentioned in section 5.1.

• what: section 5.2.2 lists the potential objects that could be adapted

• to what: section 5.2.3 looks on the factors to which the objects are adapted to

• when: section 5.2.4 covers the timing and triggering of ad-aptation

• how: the process of adapting the adaptation objects (5.2.2) is explained in section 5.2.1 for the overall adaptation process; section 5.2.5 examines the actual methods (adaptors) that perform the adaptation tasks

• how well: the evaluation of the adaptation solution is briefly addressed in section 5.2.6

The dimensions of adaptation depicted in Fig. 35 reflect the most universal structure. Another important differentiation of adapta-tion can be made for the field of cartography or visualisation in general. Whereas the dimensions mentioned in Fig. 35 refer more to adapting the mobile map to external context factors, the map in itself can internally be adapted. An example is the adaptation of text and symbol placements in order to avoid overlaps. The first case is external adaptation and the latter internal adaptation.

An internal adaptation could be understood as a self-adaptation in the sense as depicted in Fig. 12. All adaptation stages would be controlled by the system resulting in complete self-adaptive maps. An approach to self-adaptive maps is the introduction of con-straints. A proposal for using constraint-based SVG is described by Marriott et al.(2002).

(Brusilovsky, 1996) Brusilovsky, P. (1996): Methods and techniques of adaptive hypermedia, User Modeling and User-Adapted Interaction 6(2-3): 87-129

(Marriot et al, 2002) Marriott, K., Meyer, B. and Tardif, L. (2002): Fast and Efficient Client-Side Adaptivity for SVG, Proceedings WWW2002, Honolulu, Hawaii, May 7-11, 2002


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5.2.1 Adaptation process

The process of adaptation, as outlined in Fig. 36, takes several steps (Thévenin and Coutaz 1999; Calvary et al. 2001; Alatalo and Peräaho 2001). The first step is the recognition of the context, the adaptation target. The adaptation target comprises the elements to which the geographic information visualisation is adapted to. These target elements for the adaptation are recognised by the system, involving sensing the context. Some elements, such as preferences, could be predefined by the user and stored in a pro-file. The adaptation is triggered by any change or difference (between state S and state S’) of location, user, activity, information demand or system, exceeding a specified threshold. Therefore, next to sensing the context changes of context need to be detected and change measures have to be defined. Since there exist no threshold values for maps, i.e. for the context change measures, these values need to be found empirically. These threshold values indicate states where either one or all of map encoding, map con-tent, map user interface, or map visualisation do not fit the current context, i.e. are poorly adapted to this context. An adaptation could also be triggered by an event. If an adaptation is triggered, the system has to provide a reaction to the context change. The context parameters are input to the decision engine that checks, if, based on the identified context, an adaptation is necessary at all and selects an appropriate adaptation strategy. If an adaptation is triggered, the adaptation engine is invoked that selects appropriate methods with parameter settings and applies rules selected from the adaptation model. Furthermore the adaptation engine chooses the objects that will be adapted. The last step builds the adaptation execution, i.e. the construction of the adaptor. This adaptor effects the changes of the adaptation objects through applying the chosen methods, parameter values, and rules.

The design of an adaptive system or service requires at least two models (Krogsæter and Thomas 1994, p. 80 ff.):

• task model: this model describes the user tasks or activi-ties and the changing needs of the user over time; a simple model of elementary user actions has been dis-cussed in section 4.2.2

• user model: this model addresses user roles and the belonging to a user group describing different needs for different user groups or roles

Both models profit from activity theory. Further important mod-els are:

(Thévenin and Coutaz, 1999) Thévenin, D. and Coutaz, J. (1999): Adaptation and Plasticity of User Inter-faces, Proceedings i3-spring99Workshop on Adaptive Design of Interactive Multimedia Presentations for Mobile Users, Barcelona. http://research.nii.ac.jp/~thevenin/papiers/I3Workshop1999/I3Workshop99.pdf

(Calvary et al., 2001) Calvary, G., Coutaz, J. and Thévenin, D. (2001): Supporting Context Changes for Plastic User Interfaces: A Process and a Mechanism, Proceedings Joint Pro-ceedings of HCI 2001 and IHM 2001, Lille, France

Alatalo and Peräaho, 2001) Alatalo, T. and Peräaho, J. (2001): A Modelling Method for Designing Adap-tive Hypermedia, Proceedings Eight International Conference on User Modeling (UM2001) - Third Workshop on Adaptive Hypertext and Hypermedia, Sonthofen, Germany, July 13-17, 2001 http://wwwis.win.tue.nl /ah2001/papers/alatalo-1.pdf

(Krogsæter and Thomas, 1994) Krogsæter, M. and Thomas, C. G. (1994): Adaptivity: System-Initiated Individualization, in R. Oppermann (Ed.), Adaptive User Support: Ergonomic Design of Manually and Automatically Adaptable Software, Hillsdale (NJ): Lawrence Erlbaum Associates, 67-96


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• domain model: in this model knowledge about the real-world domain is captured. It is an information model that could be treated as a geo-ontology in the sense mentioned in section 4.2.4

• system model: this model keeps the knowledge about the system, i.e. the capabilities of the device, the functions available, etc.

• adaptation model (De Bra et al. 2003): the adaptation model consists of the adaptation rules that basically specify how the adaptation should be effected.

Fig. 36: Adaptation process in mobile cartography

More details on the difficult and very important question of tim-ing, i.e. triggering of adaptation are discussed in section 5.2.4. 5.2.2 Adaptation objects

Theoretically all properties and functions which play a role in the design and usage of geovisualisation are potentially adaptable objects. Fig. 37 shows these adaptable objects grouped in three categories according to the domains mentioned earlier in section 5.2. Table 11 shows these adaptable objects, further divided in more global (e.g. map style) and local (e.g. symbol size) aspects. The user interface is often shaped and constrained by the device in use. For instance, a PDA with a touch-sensitive screen allows for other interactions than a Smartphone with a keypad, thus the interaction style needs probably some adaptation. The interactive map functions’ availability or granularity could also be adapted. That means certain functions need to be hidden or aggregated to a more coarse function. Furthermore the interaction mode can be

(De Bra et al., 2003) De Bra, P., Aerts, A., Berden, B., de Lange, B., Rousseau, B., Santic, T., Smits, D. and Stash, N. (2003): AHA! The Adaptive Hypermedia Architecture, Proceedings HT'03, Nottingham, UK, 26-30 August, 2003


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adapted, i.e. depending on the current function the interaction mode is changing (e.g. from pointer to text entry). The geographic information can be adapted in different ways. Selecting, adjusting amount and level of detail (LoD), classifying, and grouping infor-mation are all forms of information adaptation. Another form is the adaptation of information encoding due to capabilities of devices or constraints of the mobile network (e.g. bandwidth). However, most important to mobile cartography is the adaptation of the visualisation. Map section and map scale are global objects adaptable in the visualisation. The visualisation method used, i.e. graphics or photo, 2D or 3D, photo-realism or abstraction can also be object of adaptation. A landmark could for instance be dis-played as an abstract symbol or a small photograph depicting the object. Dimension is another adaptable object in the visualisation process. Like in generalisation, it refers to the fact in what dimen-sion a feature is represented, e.g. a city as an area or a point element. Last but not least symbolisation parameters (graphical variables) and text attributes are adaptable. It is obvious that certain objects are constrained by or dependent on others. Not all of these potentially adaptable features in the geovisualisation process are equally adequate for adaptation. Further research will have to focus on the relevance and validity of these objects for the adaptation process. So far, it is only fair to assume that adapting all objects at once would definitely overstretch the principle of usability, the main goal of adaptation.

user interface• functions • availability

• granularity

• interaction • mode

• style

visualisation• map layout• map section• map scale• map generalisation• method• dimension• graphical elements • symbolisation

• colour

• value

• size

• form

• orientation

• pattern

• clarity

• typographical elements • font

• style

• symbolisation • ...

geoinformation• encoding• amount• classification• grouping• level of detail• geographic area

Fig. 37: Adaptable objects in the geovisualisation process


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In a next step, the adaptable objects can be listed with their attributes and value domains. The adaptation objects listed in Table 11 can be attached to different levels of adaptation.

• high level: e.g. visualisation method, encoding, scale • low level: e.g. colour, font

The level of adaptation is closely related to the granularity of the adaptation objects. In addition, one could also distinguish between morphological and structural adaptation depending on the objects affected. The morphological adaptation basically influences changes to the visual appearance in any way. The structural adap-tation affects the functionality or the internal structure of the map. Examples are the grouping and linking of map features or data structures not dependent on symbolisation. Informational adapta-tion encompasses the information per se.

adaptation objects

attribute / variable / parameter

value

map features selection {attribute|spatial|temporal}

condition grouping condition classification class definition geographic area boundingbox: xmin, ymin, xmax,

ymax map interac-tion

modality {visual, acoustic, cross-mode} style {point_and_click, forms, menus,

queries, natural language} mode {select, pan, zoom, enter} map functions pan {available, hidden, disabled} zoom … select map area … select map layer … select map object … point to … show attributes … calculate distance … calculate perimeter … calculate area … redraw {available, hidden, disabled} map layout title {presence, position, size} legend {presence, position, size} scale bar {presence, position, size} map style method/form/graphic

structure {image, perspective, map, topogram}

map section (spatial focus)

{bounding box|centre (x, y), radius r|place name|activity region}

map orientation degree map scale scale factor


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level of detail LoD generalisation operators, algorithms, parame-

ters, sequence map graphics dimension point, line, area position (x,y) colour CMYK,RGB,HSV,HEX value size {mm, px, %} orientation degree form {square, triangle, circle, ellipse} pattern { … } opacity {{0,1}|%} clarity map text map graphics attributes

+

font font_name style {plain, bold, italic, bolditalic}

Table 11: Adaptable objects of geovisualisation and their value domains

Not all the objects in Table 11 are adapted and especially not all at the same time. Without empirical studies it is hardly possible to state the objects that have to be adapted and the ones that do not have to. It is important to establish a kind of mapping table be-tween the context dimensions (adaptation target) and the corresponding adaptation objects. Furthermore the degree of adaptation, i.e. the change of attribute values, needs to be empirically found. 5.2.3 Adaptation target

In chapter 4 the primary target of adaptive visualisation, the usage context, has been discussed. The basic dimensions of context which can be adapted to individually or in any combination have been put as user, the current activity, information existent in the usage situation, and the system factors.

A pragmatic categorisation of factors influencing the adaptation of geographic information visualisation is provided by De Carolis et al. (2001). They differentiate the factors on their persistence value. The first group of factors are those that persist during time or evolve slowly. These long living factors are associated with the user, his/her characteristics, preferences, knowledge, skills, and interests etc. The other group comprises factors that are related to a specific usage situation. These factors are more context-dependent and of shorter life. The authors regard the environment (physical and social), the user activity, and the device characteristics as be-longing to these ‘context factors’.

(De Carolis et al., 2001) De Carolis, B., de Rosis, F. and Pizzutilo, S. (2001): Context-Sensitive Information Presentation, Proceedings Eight Interna-tional Conference on User Modeling (UM2001) - Workshop on User Model-ling in Context-Aware Applications, Sonthofen, Germany


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This differentiation mirrors in a way the distinction between user modelling (UM) and context modelling. Although in this work the user is considered as part of the context and would have to be modelled within the context, it is worth considering the work in the field of UM. Any adaptation to the user or personalisation re-quires a sound model of the user. Substantial research on UM has been done in the fields of web content adaptation, adaptive hypermedia, and adaptive user interfaces. Generally an individual user is the source of modelling. However, as mentioned earlier the user as a target of adaptation does not always have to be an indi-vidual, but it could also be a group of users or a whole user community. In analogy Saari and Turpeinen (2004) distinguish between user modelling (individual user profiles), group modelling (clustered profiles based on similarities), and community model-ling (profile of the social group as a whole). 5.2.4 Triggers and control of adaptation processes

The discussion of adaptation is related to the question when a map should or must be adapted. It can be argued that a map is well adapted (needing no adaptation) if it fits well into the context at hand. This means the map shows relevant information matching the user’s activity and interests, is capable of answering the user’s questions and is clearly legible on the device. These dimensions form a multidimensional value space. The space covered by all value combinations meeting the fitness function, build an adapta-tion zone. This is similar to the ecological concept of niches discussed in (Gatrell 1983, p. 147ff.). In ecology a niche is defined by the tolerance ranges for environmental factors such as tem-perature, humidity, etc. This relationship can be expressed as a function of the organism and the environmental parameters. In biology a distinction between the fundamental niche, delimited by the tolerance values, and the realised niche is made. The realised niche depends on other species. Niches of different species can overlap (ibid., p. 147). Applied to maps, it is possible to speak of map niches. The idea of adaptation zones in which a map is well adapted to its ‘environment’ is similar to the concept of map capacity for generalisation proposed by Ratajski (1967). Likewise Cecconi (2003) introduced the term limits of applicability with respects of applying LoD for different scales. Related to these two concepts is the saturation of maps indicating the threshold for the number of objects displayable on a map screen (Arikawa et al. 1994).

General UM literature for mobile com-puting: (Byun and Cheverst 2001) Byun, H. E. and Cheverst, K. (2001): Exploiting User Models and Context-Awareness to Support Personal Daily Activities, Proc. Eight Internat. Conf. on User Modeling (UM2001) - Third Workshop on Adaptive Hypertext and Hypermedia, Sonthofen, Germany, July 13-17, 2001. orgwis.gmd.de/~gross/ um2001ws/papers/byun.pdf

(Kules 2000) Kules, B. (2000): User Modeling for Adaptive and Adaptable Software Sys-tems. http://otal.umd.edu/ UUGuide/wmk/

(Specht and Oppermann 1999) Specht, M. and Oppermann, R. (1999): User Modeling and Adaptivity in Nomadic Information Systems, Proc. i3 Annual Conference: Community of the Future, Siena, Italy, Oct. 20 - 22, 1999

(Saari and Turpeinen, 2004) Saari, T. and Turpeinen, M. (2004): Towards Psychological Customization of Information for Individuals and Social Groups, in J. Karat and K. M.-C. (Eds.), Personalization of User Experiences for eCommerce (in press), Boston (MA): Kluwer Academic Publishers

(Ratajski, 1967) Ratajski, L. (1967): Phénomène des points de généralisation, in K. Kirschbaum and K. H. Meine (Eds.), Internatinal Yearbook of Cartography, 7, Bonn-Bad Godesberg: Kirschbaum, 143-152


(Arikawa et al., 1994) Arikawa, M., Kawakita, H. and Kambayashi, Y. (1994): Dynamic Maps as Composite Views of Varied Geo-graphic Database Servers, Proceedings First International Conference on Appli-cations of Databases, ADB-94, Vadstena, Sweden, June 21-23, 1994

(Gatrell, 1983) Gatrell, A. (1983): Distance and Space. A Geographical Perspective, Oxford: Clarendon Press


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For the domain of user interfaces Calvary et al. (2001) proposed a concept called plasticity. “… a plastic user interface is able to adapt to different contexts of use while preserving usability. … The plasticity domain of a user interface is the surface formed by all couples ‘platform/environment’ that this user interface is able to accommodate; the boundary of this surface defines the plasticity threshold of the user interface; and a plasticity discontinuity occurs when a change of context lies beyond this boundary“. Applied to maps, the simplest case would be, if the user moves in real space to a place that lies outside the map extent, thus the cur-rent context is not covered by the map anymore.

Fig. 38: Plasticity of user interfaces

All possible designs of a single map form a space termed the design space. An individual design, here a map, can fit its environment if certain requirements are met. Sloman (1998) argues that such a “… set of constraints and requirements for a design can be called a ‘niche’ [and that] … different designs may fit the same niche to different degrees.” In the context of design spaces adaptation can be seen as design alternatives ready to be picked by the user or self-adaptation (Totterdell and Rautenbach 1990).

The central question is when the context (all or parts of) has changed so much (measures for degree of change) that the current design, i.e. map, does not fit the context, i.e. niche, anymore and an adaptation is indicated or necessary. In analogy to biology, this change could be termed adaptation pressure. The threshold values for context change can be deferred from the generic context model and have to be found empirically. These values need to be nor-malised, generally transposed on an interval {0,1} and are possibly weighted according to their influence. The total threshold value is an addition of the single threshold values:

ytechnoormationactivityusertimelocationtotal loginf ∆∪∆∪∆∪∆∪∆∪∆=∆

(Calvary et al., 2001) Calvary, G., Coutaz, J. and Thévenin, D. (2001): Supporting Context Changes for Plastic User Interfaces: A Process and a Mechanism, Proceedings Joint Proceed-ings of HCI 2001 and IHM 2001, Lille, France

(Sloman, 1998) Sloman, A. (1998): The "Semantics" of Evolution: Trajectories and Trade-offs in Design Space and Niche Space, Pro-ceedings IBERAMIA'98, Lisbon, October, 1998



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An adaptation space is a collection of possible adaptations of a system or service, termed adaptation cases (Bowers et al. 2000). Formally, an adaptation space is a set of adaptation cases, partially ordered by the relation ‘more specialised than’.

Fig. 39: Design space, adaptation space and map niche

Bowers et al. (2000) define two spaces, performance space P and resource space R. P is dimensioned along user oriented parameters (e.g. play-out quality, response time, etc.). The acceptance region (AR) or map niche is defined as the region in which the map is considered to be working properly. R is dimensioned by resource characteristics in the operational environment (processing power, memory, bandwidth, etc.). Without adaptation there exists a map-ping M: P ⇒ R that maps AR onto region B in R. Introducing adaptation changes M so that AR now maps onto a larger region A where A normally includes B.

Adaptations may occur due to changes in qualitative aspects of usage, such as user activity, user role, place name, daytime, season, etc., or due to quantitative changes, for instance location, time, network bandwidth or device capabilities. The triggering of an adaptation through these changes invokes a strategy that deter-mines which adaptation method is most appropriate for the current context and has to be applied. The automatic application of adaptation methods by the system requires adaptation rules in the form of production rules (if <condition> then <action>) or con-straints. Both threshold values of the quantitative measures and qualitative factors can be used in such production rules. Quantita-tive factors could also be transferred into qualitative values. An

(Bowers et al., 2000) Bowers, S., Delcambre, L., Maier, D., Cowan, C., Wagle, P., McNamee, D., Le Meur, A.-F. and Hinton, H. (2000): Applying Adaptation Spaces to Support Quality of Service and Survivability, Proceedings DARPA Information Surviv-ability Conference and Exposition, January, 2000


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example is the inference from speed to a means of transport (foot, bicycle, car) and then an application of the rule if (means_of_transport) = “car” then scale = 1:150’000. In that sense an adaptive system can be understood as an expert system. For showing an adaptive behaviour, i.e. being able to perform valid and appropriate adaptations, the system must have a built-in learning component for the knowledge acquisition. Constraints can be used for adaptive maps in regard to their self-adapting be-haviour, for example the adaptation to ‘map capacity’. If a user request returned a map that is too overloaded and cluttered for a PDA, an adaptation in the form of a prioritisation would have to take place. Or, if graphical conflicts such as symbol or text overlap arise from the automatic generation of a map (Fig. 40, left), an in-ternal constraint-based adaptation could solve these problems (Fig. 40, right).

Fig. 40: Internal map adaptation based on constraints

Constraints are a common tool in design methodology and can be understood as “… a limitation that reduces the number of pos-sible acceptable solutions to a problem. … [or] a design specification to which solutions should adhere …” (Weibel and Dutton 1998, p. 2). The constraint-based approach to map generali-sation can also be used in map adaptation. Beard (1991, p. 124) distinguishes graphic, structural, application, and procedural con-straints. Graphic constraints are mainly determined by the display properties and correspond approximately to minimal dimensions. Structural constraints relate to maintaining spatial and attribute relationships. Application constraints are dependent on the map purpose and are for instance the geographic area to be displayed,

(Weibel and Dutton, 1998) Weibel, R. and Dutton, G. (1998): Constraint- based Automated Map Generalization, Proceedings 8th Interna-tional Symposium on Spatial Data Handling, Vancouver, B.C., July 1998

(Beard, 1991) Beard, M. K. (1991): Constraints on rule formation, in B. P. Buttenfield and R. B. McMaster (Eds.), Map Generalization - Making Rules for Knowledge Repre-sentations, Harlow, U.K.: Longman Scientific & Technical, 121-135


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the size and scale of the display, symbol types etc. These con-straints are strongly connected to the constraints in contexts and are most important for mobile cartography. Finally, procedural constraints specify the sequence of actions and the order in which the constraints are satisfied. Neema and Ledeczi (2003) describe a constraint-based approach to self-adaptive systems. The design space is modelled as an explicit enumeration of design alternative. An adaptation is then the transition from one element in the design space into another. A concrete example of client-side adaptivity for SVG based on one-way constraints present Marriott et al. (2002). One-way constraints allow the declaration of element attributes in SVG as expressions that are evaluated during runtime, i.e. ren-dering of the document, as the following SVG code snippet shows: <svg width="20mm" height="20mm"> <var id="boxwidth" val="url( #(/descendant::text/[ename="tl"]))-width"/> <var id="boxheight" val="url( #(/descendant::text/[ename="tl"))_height"/> <rect id="bl" class="box" x="1.0in - url(#boxwidth)/2" y="0.75in - url(#boxheight)/2" width="url(#boxwidth)" height="url(#boxheight)"/>

</svg>

Any adaptation strategy must consider the user as an important factor. As stated in section 5.1 the user should always have the overall control over the system. A good adaptation strategy has to allow the user to interfere at any time. However, the internal adaptations (self-adaptive maps) will probably not need any user interaction. External adaptations should be embodied by adap-tivity and adaptability. A combined approach, including adaptability and adaptivity, that might serve as model is described in (Krogsæter et al. 1994). 5.2.5 Adaptation methods

Adaptation methods form the last major dimension of the adap-tation concept. They are part of the adaptation engine. Their responsibility is to offer procedures to adapt the adaptation objects to the adaptation target. To get a better idea of adaptation methods it is useful to contemplate the following intuitive examples:

• if a service encounters a device with a monochrome dis-play, a colour map is reduced to grey scale

• if a service registers a significant increase in movement speed, the LoD is adjusted, i.e. the more detailed map is exchanged by a map of less detail or switches to the cor-responding LoD

In analogy to the different domains of adaptation discussed in the introduction of this chapter (see Fig. 35), adaptation methods for mobile cartography can affect the information content and

(Neema and Ledeczi, 2003) Neema, S. and Ledeczi, A. (2003): Constraint-Guided Self-Adaptation, in Self-Adaptive Software, Proceedings Second International Workshop, IWSAS 2001, Balatonfüred, Hungary, May 17-19, 2001, LNCS 2614, Berlin; Heidel-berg: Springer-Verlag, 39-51

(Marriott et al., 2002) Marriott, K., Meyer, B. and Tardif, L. (2002): Fast and Efficient Client-Side Adaptivity for SVG, Proceedings WWW2002, Honolulu, Hawaii, May 7-11, 2002, 496-507

(Krogsæter et al., 1994) Krogsæter, M., Oppermann, R. and Thomas, C. G. (1994): A User Interface Integrating Adaptability and Adaptivity, in R. Oppermann (Ed.), Adaptive User Support: Ergonomic Design of Manually and Automatically Adaptable Software, Hillsdale (NJ): Lawrence Erlbaum Associates, 97-125


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encoding, the information structure, the user interface or the information presentation. Content adaptation methods adapt map features; structural adaptation methods adapt map features, inter-action or functions; and morphological adaptation methods adapt map style, graphics and text (cp. Table 11).

The following list gives an overview of feasible adaptation meth-ods for mobile maps. These methods

• select map features (filters, e.g. based on user profiles) • reduce the map content (only few object classes) • reduce the information density (limitation to selected, impor-

tant objects and information) • remove, omit or eliminate map objects (based on map satu-

ration or capacity) • prioritise information • substitute or exchange equivalent presentations (map –

topogram – image – text – language; e.g. symbol through image)

• switch between predefined design alternatives (e.g. map symbol styles) or encodings (e.g. languages)

• change presentation; (re)change symbolisation (e.g. dif-ferent opacities for relevance) colour depth reduction; colour to greyscale; change dimensionality (area to line/point)

• (re)configure map components (e.g. different base maps or scales for different purposes or movement speeds); dynamic composition of layers for the base map (e.g. with or without public transport network)

• adapt the user interface (reducing the degrees of freedom for interactivity)

• change encoding (e.g. vector to raster, SVG to JPEG) For the adaptation of mobile geovisualisation services, the

parameters need to as ever possible be dynamically inferred from the context. The operationalisation of the parameters constitutes a big problem. If the view of Totterdell and Rautenbach (1990, p. 61) that “… conventional systems are special cases of adaptive systems in which the parameters have been pre-set” is accepted, the pa-rameter values of these conventional systems could be used to guide the operationalisation process.



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5.2.6 Evaluation of adaptation processes

The difficulties encountered when evaluating adaptations are dis-cussed by Höök (2000) and approaches for the evaluation of adaptive user interfaces are proposed in (Paramythis et al. 2001). The major problem with the attempt to answer the question when an adaptation is good is similar to the question of relevance or the quality of a generalisation solution. There are some objective crite-ria, but since the user is affected by the adaptation, there is always a subjective judgement involved.

Several methods and techniques for evaluating an adaptation are imaginable:

• the objective relevance could be used as a rough measure for adaptation quality

• the costs of the adaptation process • if a map is adapted to the network bandwidth, the docu-

ment size is a measure for the effectiveness • if a map is adapted to the user, the match between the

user profile and the features (e.g. categories) in the map indicate user satisfaction. The match could be determined by similarity measures and topical relevance

• log of user interactions (mainly the number of single interactions) after the reception of an adapted map could be an indicator for adaptation success

The last point emphasizes the need for a learning component in adaptive systems that takes the evaluation results as a feedback and improves the adaptive behaviour over time. The importance of learning has already been stressed in relation to the context space model (sec. 4.2.3), where through the user’s interaction with the system a ‘history’ of contexts is captured that can be used to provide appropriate system reactions in future usage situations.

5.3 Adaptation and generalisation As stated above, the major limitation for the geographic informa-tion visualisation on mobile devices is their small display. State-of-the-Art PDA have a display with a resolution of 240x320 pixel or a format of 60 x 80 mm. The display area ratio from an average paper map (700 x 1000 mm) to a PDA is approx. 1:150 and from a Laptop screen (12”) to PDA 1:12. Of course these figures imply the necessity for map generalisation. Some approaches for map gener-alisation for mobile maps have been discussed in chapter 3. The question arising is whether adaptation means the same as gener-alisation.

(Höök, 2000) Höök, K. (2000): Steps to take before intelligent user interfaces become real, Interacting with Computers 12(4): 409-426

(Paramythis et al., 2001) Paramythis, A., Totter, A. and Stephanidis, C. (2001): A modular approach to the evaluation of Adaptive User Interfaces


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Many researchers in the cartographic community do not see small display cartography or mobile cartography as an inde-pendent research field in the discipline. They believe that mobile cartography is basically a matter of map generalisation with very hard constraints due to the small display. The author argues that more fundamental issues linked to mobility are involved, and hence aims at elaborating where generalisation and adaptation are different and where they do overlap.

The author holds the opinion that generalisation and adaptation are related concepts, but that generalisation is more objective, aiming at reflecting the basic characteristics of map elements and their distribution in a preferably uniform and balanced manner. Adaptation is more subjective. The balance is often abandoned for the sake of emphasizing a relevant element. Furthermore, adapta-tion as understood in this work considers more factors than scale and map purpose usually applied in generalisation. Generalisation is mainly caused by the technology dimension, i.e. the small device display. As aforementioned, adaptation principally takes into account the context of the map usage, i.e. location, time, user, activities, goals, information around, and technology. In addition, adaptation potentially affects more objects in the cartographic design process.

Two different approaches for applying adaptation and generali-sation are feasible: either generalisation first and adaptation second or adaptation first and generalisation second. Nevertheless in the author’s opinion adaptation is the more general concept affecting objects in the cartographic design process that are not covered by generalisation (e.g. colour). In this sense, methodologically one would first apply adaptation and then generalisation. Adapting to a specific usage situation reduces the problem space for succeeding generalisation. Adaptation, however, might also make use of gen-eralisation methods, but implements them differently. This is possible, since methods of adaptation and generalisation are very similar. The most important method for adaptation to mobile geo-graphic information usage as well as generalisation for small displays is selection. Other well known generalisation operators applicable as an adaptation method are exaggeration, elimination, combination, and typification.


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Adaptation Generalisation

broad narrow emphasis abstraction fitness to use fitness to scale adaptation to context adaptation to scale

Table 12: Comparison of adaptation and generalisation

Table 12 summarises the major characteristics of map adaptation and map generalisation. It is obvious that the two concepts are not concurrent, but are completing each other.

5.4 Adaptive visualisation of geographic infor-mation on mobile devices As discussed in chapter 3, little research has been conducted so far on the visualisation of geographic information on mobile devices. However, there are a few guidelines for the design of screen maps in general. Some of the solutions and approaches provided can also be applied to mobile cartography, but need some modifica-tions or additions.

There are many research questions dealing with the design of geovisualisation services, see for example (Reichenbacher and Meng 2003; Zipf 2002). As a wrap-up this allows for a preliminary list of requirements for adaptive geovisualisation services. Adap-tive geovisualisation services should be:

• personalised • minimal intrusive • location-based • timely • context-aware • attentive • proactive • reactive • prioritised

To meet these requirements at least partially, new or enhanced visualisation methods are demanded. Before these new ways of visualising geographic information in mobile environments will be studied, a few scenarios of mobile geographic information usage are sketched. 5.4.1 Scenarios for adaptive visualisation of geographic information on mobile devices

As mentioned above the concept of mobile cartography might seem to many people quite visionary. The author tried to explain why it is crucial to the discipline of cartography to cope with new

(Reichenbacher and Meng, 2003) Reichenbacher, T. and Meng, L. (2003): Themenheft 'Mobile Kartographie', Kartographische Nachrichten(1 & 2)

(Zipf, 2002) Zipf, A. (2002): User-Adaptive Maps for Location-Based Services (LBS) for Tour-ism, in K. Woeber, A. Frew and M. Hitz (Eds.), Proc. of the 9th Internat. Conf. for Information and Communication Technologies in Tourism, ENTER 2002, Innsbruck, Austria, Springer Computer Science, Berlin; Heidelberg: Springer-Verlag. http://www.eml.villa-bosch.de/ english/homes/zipf/ENTER2002.pdf


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technologies and adapt its methods to new challenges. As a proof of concept a few example usage scenarios are sketched. The sce-narios are set in an urban context. One reason is that the base technologies, mobile communication infrastructure and mobile devices are first installed in urban areas. Besides the consumer base is larger in densely populated areas such as big cities. Another factor is the huge bandwidth of spatially-related activities and the immense availability of options for leisure, shopping, work etc. Another reason is related to technology adoption: urban lifestyle followers tend to adopt new technologies faster than other popu-lation segments. In his theory of technology diffusion Moore (1991) distinguishes 5 phases of technology use or 5 groups of tech-nology users: innovators, early adopters, chasm, early majority, traditionalists. The second group, the early adopters, is of special interest for the design of the following usage scenarios. This group is technology focussed, willing to take risks, wealthy, keen on new gadgets, optimistic, and visionary. The innovator group is also the peer group for potential adopters of the future majority.

The difficulty in analysing the requirements of a new mobile geo-visualisation service with adaptation capabilities is that most peo-ple if asked to name their demands have problems in articulating them without a prototype. This is due to the mutual influence of activities and technologies to support them. This observation is described by Carroll (2000, p. 67) as the task-artifact cycle:

In the large, information technology appears as a coevolution of tasks and artefacts. People engage in tasks and activities. They make discoveries and encounter difficulties. They experience in-sight and satisfaction, frustration, and failure. At length, their tasks and experiences help to define requirements for future technology. Subsequent technological tools open up new possi-bilities for tasks and activities, new ways to do familiar things, and entirely new things to do. They entrain new skills to learn and perform, new opportunities for insight and satisfaction, and new pitfalls of frustration and failure. Ultimately the new tasks and new technology become a baseline, helping to evoke require-ments for further technology development. This pattern, … the task-artifact cycle, emphasizes the dynamically moving window of technology development within which technical design occurs … . The task-artifact cycle is pervasive in information technol-ogy.

(Caroll, 2000) Carroll, J. M. (2000): Making use: scenario-based design of human-computer interactions, Cambridge (MA): MIT Press

(Moore, 1991) Moore, G. (1991): Crossing the Chasm - Marketing and Selling Technology Products to Mainstream Customers. New York (NY): Harper Business


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Apart from the agreement that geographic information is a key demand in mobile or wireless services, studies on more concrete user requirements are rare. Yet, to capture some potential requirements for the prototypical implementation of a geovisualisation service a scenario-based design approach was taken. According to Jarke et al. (1998) “a scenario describes (textu-ally or graphically) a possible set of events that reasonably take place; a scene captures the same in some form of multimedia” and thus is a middle-ground abstraction between models and reality. Scenarios are like little stories telling which activities people do in specific situations. As stories they mention or presuppose a setting, include agents or actors with goals or objectives (Carroll 2000). A scenario illustrates what people can do with a new system or how this system can be used. In this sense they are a good method for describing user roles within a context or what has been termed “lifestyle snapshots” (ui 2000). Scenarios are valuable here, because they are centred on the user’s activities:

Scenarios evoke task-oriented reflection in design work; they make human activity the starting point and the standard for de-sign work. Scenarios help designers identify and develop correct problem requirements by being at once concrete and flexible. They help designers to see their work as artefacts-in-use and, through this focus, to manage external constraints in the design process. Scenarios help designers analyze the varied possibilities afforded by their designs through many alternative views of usage situations. And scenarios help designers cumulate their knowledge and experience in a rubric of task-oriented abstrac-tions (Carroll 2000, p. 68f.).

Scenarios fit in the overall usability design process. Fig. 41 shows a general process of user requirement analysis and the role of sce-narios within that process (BTexactTechnologies 2003).

(Jarke et al., 1998) Jarke, M., Tung Bui, X. and Carroll, J. (1998): Scenario Management: An Interdisciplinary Approach, Requirements Engineering Journal 3(3): 155-173

(ui, 2000) ui (2000): Lifestyle Snapshots - Solving the Context Problem for Wireless Design, ui - The Webzine for Interaction Designers. www.uidesign.net/2000/papers/ lifestylesnapshot.html

(BTexact Technologies, 2003) BTexactTechnologies (2003): Usability matters - A methodology for the design of high usability internet content, White-paper, 42742, BTexact Technologies, Ipswich


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Fig. 41: Scenario based design approach (BTexactTechnologies 2003)

For the test implementation and the scenarios a city district of Munich called Gärtnerplatz has been selected (see Fig. 42). This dis-trict is very close to the centre, hosts a major theatre, a famous technical museum, and many bars and restaurants. Most of the people living here, but also those spending their leisure time in the area, are part of the ‘yuppie’ segment and belong to the early adopter group.

Fig. 42: Test area (map from Neudeck 2001)

Scenario 1: YUPPIE

Susan and Martin have just left their flat in the north of Munich. They are on their way to the city centre to have a good time with some friends. While Susan is driving, Martin checks on his PDA for bars with attractive Happy Hour offers and decides to go to the Indian Bar. To


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know how much time they have left for finding a parking space he checks if their friends are also already on their way and where they are. Instead of calling them one by one or sending them an SMS, a quick look on the map suffices to see that they are not further than Susan and Martin. To guide Susan he searches for the nearest park-ing storey with spaces available. He does not know this area very well and especially has no knowledge of the one-way roads here. To be on the safe side, he has the system propose the fastest route that also includes the current traffic situation. Five minutes later Susan parks the car and the system displays them the way to the Indian Bar where they wait for their friends while enjoying a cocktail.

The key issue in this scenario is the partial unfamiliarity with the surrounding and the community aspect of young urban lifestyle people. Additionally the aspect of time criticality is exemplified. For car drivers decisions have to be made rather quickly. Scenario 2: MACHO

Friday evening, 18:57, close to ‘Viktualienmarkt’. Once again John is at the last minute heading for a bunch of his girlfriend’s favourite flowers. It is her birthday today. The booths on the market are of course sold out by now; time is getting scarce. He enters a spatial search for the nearest flower shop in his PDA and the received map shows him that the nearest flower shop closes at 19:00. He changes the spatial scope of the search and gets the nearest open shops. The on-the-way-home function chooses the shop closest to the route home. After having purchased a huge bunch of flowers, he presents it slightly exhausted at 19:20 to his girlfriend and they spend a relaxed evening.

In this scenario the user is a male resident knowing the spatial environment very well, i.e. has a strong mental map, but is forced to make a quick decision. For users familiar to the geographic area an adaptation could include another, more generalized base map and fewer or different landmarks. Scenario 3: TOURIST

At 13:47 after a walk through the old part of Munich Claire Bouderin, a French tourist would like to know where she is. After a look at the map on her PDA that shows her current position, she decides to go for a shopping tour. In addition she would like to visit the ’Deutsches Museum’ for at least two hours. Before visiting the Museum she wants to drop in at the hotel and leave her purchases there. The system proposes a route passing the major shops and leading to the hotel. Calculating backwards from the closing time of the museum and the time to reach it from the hotel, alerts to pass on are regularly dis-played on the map and notified with sounds. Claire manages to resist a tempting shop and arrives at the hotel at 15:00. On the way to the museum she searches for restaurants in the neighbourhood and events in walking distance of these restaurants. Happy with the of-fers, she books a ticket for an opera at the ‘Staatstheater am Gärtnerplatz’ that is close to a typical Bavarian restaurant she has de-cided to go to for dinner after the museum visit.


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The significant momentum in this scenario is the unfamiliarity of the user with her spatial surrounding. The user has no mental map of her surrounding. The base map must be much more detailed and show the basic structure of a city in Lynch’s sense. The map should be poster-like, striking, and pithy. For tourists the public transport network is important. This can be visualised as a topogram connected with the time table. Further information needs of tourists are sightseeing spots (POI), food and drink, accommodation, and service points (ATM, kiosks, toilets, etc.).

The different treatment of familiar and unfamiliar geographic en-vironments is an important issue in spatial cognition, see for some examples in (Lovelace et al. 1999). This geographic familiarity has a strong influence on the selection and number of landmarks and map labels to be integrated in the map. A detailed discussion of criteria and measures for the selection of landmarks can be found in (Raubal and Winter 2002). An approach for automatically ex-tracting landmarks from geospatial data is proposed by Elias (2002).

In addition to the scenarios mentioned before, a few other ideas of map-related services are:

• everyday life planner: activities are shown on a map and can be visualised according to their time schedule. New activities can be added by selecting in the agenda drop-ping on the map. The service notifies, e.g. with blinking symbols or sounds, if activities get in conflict or following activities cannot be performed in time. Such a service could be termed ‘spatial diary’, since it gives the user in addition to the temporal aspect a holistic overview of the spatial distributions of appointments or other activities. With an agent approach, an agent could autonomously adapt the activity plan, inform affected persons (e.g. appointments) if needed and propose alternatives. This kind of service combines decision support systems (DSS) and geographical information systems and presents all the plan information in a spatio-temporal framework.

• computer supported cooperative work (CSCW): the aspect of collaboration, touched in the preceding example, could be extended to a service supporting mobile work forces co-ordinating their activities, information, etc. with one another

(Lovelace et al., 1999) Lovelace, K. L., Hegarty, M. and Montello, D. R. (1999): Elements of Good Route Directions in Familiar and Unfamiliar Environments, in C. Freksa and D. M. Mark (Eds.), COSIT'99, LNCS1661, Berlin; Heidelberg: Springer-Verlag

(Raubal and Winter, 2002) Raubal, M. and Winter, S. (2002): Enriching Wayfinding Instructions with Local Landmarks, in M. J. Egenhofer and D. M. Mark (Eds.), Geographic Informa-tion Science: Second Int. Conf., GIScience 2002, Boulder, CO, USA, September 25-28, 2002. Proceedings, LNCS 2478, Berlin; Heidelberg: Springer-Verlag, 243-259

(Elias, 2002) Elias, B. (2002): Automatic Derivation of Location Maps, Proceedings IAPRS Vol. 34, Part 4 Geospatial Theory, Processing and Applications, Ottawa, Canada


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• community services: an example of such a community ser-vice is described by Kolbe et al. (2003)

• visual journal service: (where have I been today?) 5.4.2 Adaptive visualisation methods for geographic infor-mation on mobile devices

For this work, the adaptive geovisualisation service will produce mobile maps. Such mobile maps are simple and highly gener-alized, should be based on cartographic principles, rendered fast, graphically concise, attractive, crisp, and legible. In addition their content should be flexible, i.e. the content should be dynamically updateable and linkable to other information. They should be adaptive to different users, activities, and situations and fit other web services. At least these services must be capable of displaying points of interest (POI) and landmarks, the geolocation of people, objects, and events, routes, and search results (i.e. people, objects, events). They should also visually emphasize order in relation to relevance, importance, priority, availability, time criticality, etc. Scalable Vector Graphics for adaptive mobile maps

The vector approach has some advantages over the raster format, such as smaller file size, flexibility, which will be honoured in the mobile environment. Among different vector formats on the Web, SVG seems to be especially useful for good reasons. SVG has a couple of features making it almost predestined for usage on mobile devices:

• open XML based format • compact, i.e. small file size • programmatically changeable through the Document

Object Model (DOM) • scriptable using the DOM • linkable • adaptable • legible, i.e. no detail loss while zooming; better text read-

ability • searchable • animations are incorporated

If this list of features is compared with the requirements of adap-tive maps or an adaptive geovisualisation service, a significant match is obvious. Neumann and Winter (2000) describe the fea-tures of SVG that can be applied to cartography. From a cartographic perspective the prominent elements of SVG are the <path> element for describing irregular geometric boundaries of map features, the <g> tag for grouping similar map elements for

(Kolbe et al., 2003) Kolbe, T. H., Steinrücken, J. and Plümer, L. (2003): Cooperative Public Web Maps, Proc. 21st Internat. Cartographic Conf., Durban, S. Africa, August, 10-16

(Neumann and Winter, 2000) Neumann, A. and Winter, A. (2000): Kartographie im Internet auf Vektorbasis, mit Hilfe von SVG. http://www.carto.net/papers/svg/index_d.html

SVG & Cartography: www.carto.net


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symbolisation or manipulation, the <script> tag for including some logic into to documents allowing for interactivity or event-based manipulation of elements, the <textPath> element which can display texts along a path, and eventually the <symbol> and <use> tag to define reusable elements such as point symbols.

Meanwhile quite a few map applications and projects use SVG as format (see for examples on www.carto.net). Although these examples address rather the desktop web mapping environment, they show the advantages and major methodology that will also apply to some degree for mobile cartography. SVG 1.0 was mainly designed with desktop PCs in mind. It works well for them as the applications mentioned above show. However, since mobile devices can differ quite a lot in their characteristics and are all more or less limited compared to desktop PCs, SVG 1.0 runs into some problems in the mobile environment. The current specification SVG 1.1, a W3C recommendation, tackles this problem. The modularisation of SVG 1.1 lays the basis for an adapted subset of SVG more suitable for mobile devices. In SVG 1.1 the content of SVG 1.0 plus some additional features are grouped into a set of modules. Mobile SVG uses these modules to set up two profiles, SVG Basic and SVG Tiny that are part of the 3GPP platform for third generation mobile phones. SVG Basic is aimed at PDAs and SVG Tiny at mobile phones. SVG Basic is of special interest for the purposes of a more advanced geovisualisation service as used in this work. It comprises a subset of the 1.1 modules. The idea is that SVG 1.1 can be transcoded to SVG Basic with the least loss of func-tionality necessary. Apart from text, clipping, and filter module all modules of SVG Basic correspond to the full specification of SVG 1.1. Information organisation concepts and information layering

Structuring relates to the decomposition of a mobile map into several single SVG documents, but also to the arrangement of unique elements or layering within a single SVG document. A first simple approach is the separation of the geospatial information into two groups: the core layer is constituted by the base map in-cluding the geometric reference, (e.g. buildings, major roads, rivers and so on), maybe enriched by public transport network and major landmarks. The second group are the superimposed thematic lay-ers of information that will be changed more often and maybe dynamically (e.g. POI, routes, point symbols, further text/labels, dynamic landmarks, geolinks, routes, directions, events, weather, traffic information etc). The base map and the dynamic map are

SVG

SVG 1.1 Specification: www.w3.org/TR/SVG11 Mobile SVG Profies: www.w3.org/TR/SVGMobile


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stored in separate SVG documents. These additional layers can be referenced from the main map, generally the base map, as SVG fragments using xlink:href. With geospatial hyperlinks (geo-links) the representation of associations between different resources (features, images, documents, etc.) become possible.

In a single SVG document the structure affects order, grouping, and reusability of elements. Most importantly the order of ele-ments in the document has the major impact on the visualisation, due to the SVG rendering principle which paints the elements in the document in the order of appearance. Point symbols within a SVG document can for instance be defined as <symbol> within the <defs> tags at a central place and be referenced using the <use> tag and an xlink:href at the place needed. The referencing of external SVG documents is currently only supported by the Batik 1.1 Squiggle Browser. Adaptation methods examples with SVG

For some of the adaptation methods discussed in section 5.2.4 a counterpart can be found in geovisualisation adaptation. In the following some adaptation methods are described as a combina-tion of map theory (syntactical rules, e.g. graphical variables) and constraints of mobile devices (e.g. graphical effects of raster tech-nology).

Probably the most important task in adapting the geovisuali-sation is highlighting important features to emphasize their importance or relevance. Graphical means to put a visual empha-sis or focus on a feature are:

• highlighting the object using a signal colour, e.g. pink or yellow (colour)

• emphasizing the outline of the object • enhancing the contrast between the object and the back-

ground • increasing the opacity of the object while decreasing the

opacity of the others (opacity) • focussing the object while blurring the other objects

(crispness) • enhancing the LoD of the object against that of the other

objects • animating the object (blinking, shaking, rotating, in-

creasing/ decreasing size)

Apache Batik: xml.apache.org/batik


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Fig. 43: Methods for emphasizing map objects: opacity and crispness

Fig. 43 shows two examples of relevance symbolisation using the graphical variable opacity (left) and crispness (right). Size is not a useful graphical variable, because the map space is limited any-way. An exception is the use of size as a variable of animation, e.g. the increasing and decreasing of size by clicking on a map feature or text label.

Apart from emphasizing a single object, these methods allow for visualising a relevance order. This method is very useful for ren-dering symbols for POIs with different opacities depending on their relevance. The total relevance value from the event example (see Table 10) can be directly mapped to the opacity value of the SVG style attribute. The result set of a search activity can contain geospatial objects, people or events and can be sorted according to different criteria. Relevance is only one example. Others are avail-ability, costs, etc.

The spatial relevance of map features might also be visualised with buffers depending on the spatial relevance measure. Data quality or context validity can be visualised as zones that can be transparently overlaid over the actual geographic information. Also other information types could be overlaid as additional semitransparent layers, e.g. a compass for orientation purposes (Fig. 44, left), the map scale as a distance ring or buffer or temporal reachability as time rings (Fig. 44, right). The user can interactively switch on and off such information.

The geometric basis depicted in Fig. 43-44, Fig. 45 left, Fig. 46 right, Fig. 48-51, and Fig. 57 are all based on data form and are copyright ‘Städtisches Vermessungsamt München’ Fig. 45 right and Fig. 47 are based on data from and are copyright ‘Bayerisches Landesvermessungsamt’, München


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Fig. 44: Semi-transparent overlay in mobile maps for orientation or dis-tance information

Less important or less relevant information can be displayed as layers or groups of map features with lower opacity or lighter col-our. This moves this information in the visual middle ground and emphasizes the more important information. This could also be interactively initiated and reversed by the user. Similarly the base map could be dimmed out radially from the user position or bi-directionally for routes towards the edges of the map enhancing the spatial focus. To visually highlight the area of interest or focus, an activity zone or a search area, the method of overlaying a trans-parent polygon or circle can also be applied. This is useful for route visualisations where the route and the landmarks are in the visual focus and the other information should only function as the con-necting geospatial frame.

The change of activities can also result in a change of spatial scope. For example the first user activity has a local scope, thus a large scale map is used. Then, the user performs an activity with a regional scope. The large scale map is not covering the whole area of interest for the activity and a change of scale is appropriate. The change of mobility medium can have the same effect, for example the change from walking to riding a bus. Fig. 45 shows two base maps of different scales.


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Fig. 45: Map scale adaptation

Hierarchy in user activities according to AT (activity, action(s), and operation(s)) should be if possible mirrored in a hierarchy or sequence of information presentation: e.g. from an overview map to a detail map, from an overview schematic map (or topogram) to a detailed map or first an address search, second display of ad-dress location on map, and third textual route description to the address. The begin of an activity can be triggered by a local action requiring a local map. The planning or further performance of the activity might require a more global map, and the actions to take again further local maps.

When regarding the usability of a map, an important criterion is utility in the sense of being useful for conducting the current activity. There is no consistent terminology for maps that are designed for user activities: egocentric maps, focus maps (Zipf and Richter 2002), aspect maps (Barkowsky and Freksa 1997), topic maps, or activity-based maps (von Hunolstein and Zipf 2003). The view taken here is that maps applying adaptation methods as mentioned before can be termed ego-maps, because they are ego-centric in the sense that the user is in the centre. This centre can be the spatial centre, the centre of activity, the centre of interest and so on.

An activity map is a map that is adjusted to the current user activity and focuses on one or more included elementary spatial action (locating, navigating, searching, identifying, and checking). The view to design a product or service around a user activity is best grasped by Rosson and Carroll (2002, p. 81) stating:

We prefer the phrase “activity design” because it emphasizes the broad scope of what is being designed: people carrying out activi-ties with the support of computer software. It is essential to design software systems in a usage context, always considering whether and how they will support human goals and activities.


(Barkowsky and Freksa, 1997) Barkowsky, T. and Freksa, C. (1997): Cognitive Requirements on Making and Interpreting Maps, in H. S. and A. Frank (Eds.), Spatial Information Theory A Theoretical Basis for GIS, Berlin; Heidel-berg: Springer-Verlag, 337-361

(von Hunolstein and Zipf, 2003) von Hunolstein, S. and Zipf, A. (2003): Towards Task Oriented Map-based Mobile Guides, Proc. Internat. Workshop "HCI in Mobile Guides" at Mobile HCI 2003, 5th International Symposium on Human Computer Interaction with mobile Devices and Services, Udine, Italy, September 8-11, 2003 (Rosson and Carroll, 2002) Rosson, M. B. and Carroll, J. M. (2002): Usability Engineering: Scenario-Based Development of Human-Computer Interaction: Morgan Kaufmann


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Such an approach requires an activity ontology or activity typology. McCullough (2001) proposes a preliminary typology of everyday ‘situations’ relevant for mobile services. The four main ‘situations’ are at work, at home, on the town, and on the road, each asso-ciated with activities such as crafting, collaborating, watching, cruising, eating, shopping, sporting, hoteling, touring, driving, walking, etc. Accord-ing to McCullough (2001, p. 345) “design that recognizes how these activities occur ‘habitually and in a state of distraction’ has a better chance toward usability, assimilation, and getting out of the way.“ A more formalised way for establishing an activity ontology is described by Kuhn (2001) using the example of actions found in German traffic code. The ontology is derived from textual descrip-tions and models the relationships between actions and objects. In addition an ordering of the actions in a hierarchy of traffic actions is accomplished. Wang and Cheng (2001) offer a spatio-temporal data model to support activity based transport demand modelling in a GIS environment. Their approach models activity patterns as a sequence of staying at or travelling between activity locations and supports location-based, time-based, and person-based analysis and querying of activities. The notion of activity patterns suggests that some activities show regularities regarding space and time (e.g. locations, sequence, and frequency) and can be attached to specific geospatial objects.

Despite setting up activity ontologies activity zones have to be modelled for the purpose of activity maps. An activity zone can be defined as the region or spatial scope of an activity (see Fig. 22). However, the zoning cannot always easily be done based on geometry, because for activities other dimensions are important. Von Hunolstein and Zipf (2003) refer to social zoning as a way for searching for clusters of facilities, events or attractions within cities. The example depicted in Fig. 46 (left) gives an idea of an activity map taken from Graham and Kjeldskov (2003). Robert Kauper, a colleague at the Department of Cartography, developed a similar example depicted in Fig. 46 (right). The map visualises the move-ment of underground and tramways around the Technische Universität München in real-time. The animation is based on the time-table and implemented using JavaScript. Both examples demonstrate how useful this kind of geovisualisation can be for the support of everyday activities (e.g. catching a tramway).

(McCullough, 2001) McCullough, M. (2001): On Typologies of Situated Interaction, Human-Computer Interaction 16: 337-349

(Graham and Kjeldskov, 2003) Graham, C. and Kjeldskov, J. (2003): Indexical Representations for Context-Aware Mobile Devices, Proceedings IADIS International Conference on e-Society, Lisbon, Portugal, June 3-6, 2003

(Kuhn, 2001) Kuhn, W. (2001): Ontologies in support of activities in geographical space, International Journal Geographical Information Science 15(7): 613-631

(Wang and Cheng, 2001) Wang, D. and Cheng, T. (2001): A spatio-temporal data model for activity-based transport demand modelling, International Journal Geographical Information Science 15(6): 561-585


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Fig. 46: Route-focussed maps

In the following several examples of maps adapted to specific elementary user actions are presented. Locating

Simple forms of location maps show the user’s current position on a map. This can be done with a YAH symbol. If accuracy values for the position are available, the position could be marked along with a tolerance circle around it. Furthermore the positions of objects and other people could be presented in location maps.

Fig. 47: Location map

Navigating

Route or navigation maps focus on the route and the necessary landmarks for getting a route overview or direction following. The map in Fig. 48 (left) shows the symbolisation of routes with differ-ent colours depending on the modality (bus and walk). The map example in Fig. 48, right illustrates the emphasizing of the public transport network.


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Fig. 48: Route maps

Searching

A map related to a search action presents the search result in maps. The map example in Fig. 49 shows the result of a search for thea-tres and bars. In addition to thematic or category search, spatial or temporal conditions (e.g. proximity) can be applied to refine the search. Interesting is the integration of social zones in the search process. Instead of Euclidean space, more activity oriented spaces can often be more appropriate.

Fig. 49: Search result map

Identifying

The example in Fig. 50 shows the use of a popup information box that gives further details about the identity of a selected geospatial object. Such informative ‘boxes’ compensate for the reduced information density of the map.


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Fig. 50: Map with further information for identified feature

Checking

Maps showing events or the state of objects can either show the qualitative or quantitative differences. Qualitative differences can comprise event type, availability, state, etc. The example depicted in Fig. 51 shows the state regarding available spaces of multi-storeys. The multi-storey with free spaces is displayed in full opacity, whereas the second one with no vacancies is displayed with a lower opacity. Similarly the bars that are closed at the moment are displayed with lower opacity.

Fig. 51: Event and object state map

This method catches the user’s view and directs it to the impor-tant and more relevant information without completely neglecting other information that could become important. An example of a quantitative difference is the water temperature of outdoor swim-ming pools. Functionality

A good example of an adapted map function is the ‘helicopter zoom’ tool built in the Falk City Guide product (Fig. 52, left). This tool zooms out (as if a helicopter would lift up) and displays the map smoothly up to a smaller scale showing less detail. This gives the user an overview and shows the spatial context. After a

Falk City Guide:

www.falk.de

Pocket Street Map: www.streetmap.co.uk


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moment of time the tool zooms back to the original zoom level. Another example of a map specially designed for mobile devices is Pocket Streetmap (Fig. 52, right).

Fig. 52: Design for mobility: Falk Cityguide and Pocket Streetmap

Information for which there is not enough space on the map can be switched on and off by clicking on hot spots. Relevant text labels (e.g. street names) can for instance be selected from database and incorporated in the map as hidden elements. By clicking on the map feature the hidden text is switched to visible through an ‘animation’ and switches back after a while or another click. The same method can be applied to the map legend that is only visual-ised on-demand. Other visualisation tools

As mentioned in different places of this work, there are more ways to communicate geographic information on mobile devices than just maps. Apart from vector maps, orthophotos, photo-graphs of landmarks or POIs, 3D views derived from city models (e.g. VRML or X3D), perspective views (Fig. 53, left), silhouettes of important geospatial objects, e.g. landmarks (Fig. 54), and 3D sym-bols (Fig. 53, right) are alternative ways of presenting geographic information.


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Fig. 53: Perspective views (left) and 3D landmark symbol (right; © Falk)

Fig. 54: Silhouette view of landmarks (Gartner 2003)

Fig. 55 shows an orthophoto with a thematic overlay. Several problems arise with the use of images. Firstly, the size of (raster) images is generally bigger than for vector maps. Secondly, the usage of text on top of images leads to the known legibility problems. And finally, the lacking abstraction makes it difficult to extract information efficiently. On the other hand, an orthophoto is useful to give a general impression of the geography and helps to get an overview of the activity region.

Fig. 55: Orthophoto with thematic overlay (Image: © Bayerisches Landesvermessungsamt, München)

(Gartner, 2003) Gartner, G. (2003): Pedestrian Naviga-tion Services: A Multimedia Cartography Approach To Mobile Internet Applica-tions, Proceedings 21st International Cartographic Conference, Durban, South Africa, August 10-16, 2003


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Furthermore, multimedia maps combining images, video, text, sound and graphic or animated maps are an imaginable means to communicate geographic information on mobile devices. These kind of maps are beyond the scope of this dissertation; for an ex-ample see (Gartner 2003). Besides performance issues, their ability and value in efficient geographic information presentation has still to be proven.

From the experience gained with the design of the mobile exam-ples following recommendations for the design of mobile maps can be given:

• low information density • high generalisation degree • primacy of relevance over completeness • poster-like style • unobtrusive base map • drastically enlarged minimal dimensions • no fine design elements from paper maps; no patterns

and contours • colour as main design element (value and saturation), but

not too many colours in the same map • thrifty use of text; only sans-serif fonts • self-explaining, pictogram-like symbols

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Chapter 6

6 Service design for integrating adaptation into geovisualisation

The wireless telegraph is not difficult to understand. The ordinary telegraph is like a very long cat. You pull the tail in New York, and it meows in Los Angeles. The wireless is the same, only without the cat. – Albert Einstein

6.1 Use cases for adaptive geovisualisation ser-vices on mobile devices

After the discussion of methods for mobile geovisualisation, some of these ideas are implemented in a prototypical geovisualisation service. The implementation is far from complete. It aims at dem-onstrating the feasibility of the adaptation approach and at serving as proof of concept. For matters of simplicity only the case of POI maps is implemented. However, the simplicity allows for grasping the essence of the approach and reveals the possible enhancements and extensions. Apart from demonstrating the concept of adapta-tion, the goal of this chapter is to propose a possible design of an architecture for adaptive geovisualisation services. First, a few use cases are sketched based on the scenarios developed in the pre-ceding chapter. ”A use case is a typical interaction between a user and a computer system [that] captures some user-visible function [and] achieves a discrete goal for the user” (Fowler and Scott 1997, p. 43). The use cases lay the ground for the implementation plat-form. Secondly, the overall architecture, the hardware and soft-ware platform used, and the test bed are described. Thirdly, the partial implementation of the functionality is documented.

In mobile cartography the two most general use cases are the

stationary and mobile usage: the device is first used station-ary, stand-alone with fixed network connection (e.g. at home) and later mobile with a wireless network connection

(Fowler and Scott, 1997) Fowler, M. and Scott, R. (1997): UML Distilled: Applying the Standard Object Modelling Language, Reading (MA): Addison-Wesley


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(e.g. on a trip). An example for such a use case is trip planning on a desktop machine with loading the required static maps and other relevant and foreseeable information on the mobile device (generally over a synchronisation process). On the trip the user only downloads further dynamic, unforeseen or changed information to his/her device. mobile usage: the user is mobile and has no information related to the current usage situation on the mobile device. Information relevant to this situation is downloaded over a mobile network and adapted due to changes in reality (in the environment) or due to spontaneous decisions.

Depending on these general use cases described above and the capabilities of the device as well as the network infrastructure the following cases for adaptation can be imagined:

• a completely new map is generated and adapted on the server and sent to client for rendering

• only adapted fragments of information content are sent to the client and replaced (e.g. only SVG documents holding the new information are sent with references to the client). A somewhat different approach of incremental updating on mobile devices is proposed by Girow (2003).

• the adaptation is performed completely on the client-side (e.g. with JavaScript). The amount of data and function-ality to be stored on the client is big. However, if all the necessary information is stored locally and the position-ing technique is embedded in the device (e.g. GPS receiver), an autonomous adaptation is possible, at least a continuous client-side position tracking and mapping.

So far no statement can be made about whether the adaptation should take place server-side, client-side or in a mixed constella-tion on both. It must be tested in practice and the tradeoffs, such as waiting time, network bandwidth, download costs, processing power, memory requirements, need to be studied. The strategy itself is probably dependent on the usage situation. For the posi-tioning it is obvious that most users feel more comfortable, if they know the position is calculated by their device and not on a service provider’s platform.

The requirements for the ‘mobile’ use case could be described as follows: the system must recognise the usage situation X, indicated by the context indicators i1, i2, i3, … After that the system needs to

(Girow, 2003) Girow, A. (2003): Incremental SVG mobility and update, Proceedings SVG Open 2003, Vancouver, Canada. http://www.svgopen.org/2003/papers/ Incremental_SVG_mobility_and_update/


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define the context and the goal of adaptation. Then it selects an appropriate service and configures this service based on the con-text parameters. Possibly adaptation is iterated until the adaptation goal is met.

The system, i.e. the client application provides the following context parameters automatically: position, time, user, and device. The user has to select one of the elementary actions: locating, navi-gating, searching, identifying, and checking. Depending on this selection different additional parameters have to be defined by the user in the different use cases as shown in Table 13. Locating

task

mode parameter(s) system functions additional service(s)

select item to locate

person id, name contacts list

object list of POI geocoder address street,

house nr address list geocoder

place place name gazetteer, reverse geocoder

Navigating

task mode parameter(s) system functions additional service(s)

select start, end, mid points

show graphically

click ‘mouse’ listener

coordinate x,y value text entry mask geocoder object object-id,

click list of POI, ‘mouse’ listener

geocoder

address street, house nr

address list geocoder


select kind of routing

routing criteria

routing criteria

selection list

Searching

task


select category

code, name click category list

select attributes

attribute domains

x,y value menu, text entry mask

select search area

distance radius

metres, minutes

predefined list, text entry mask


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Identifying

task


select item show graphically




geocoder

Checking

task


select item for check

show graphically




geocoder

address street, house nr

address list geocoder


select time frame

date or time date or time text entry mask, calendar

Table 13: Use cases for the elementary spatial actions

6.2 Implementation of a prototypical adaptive geovisualisation service For the design of a prototypical geovisualisation service a few basic assumptions have been made. The client is supposed to be a PDA (or a Smartphone) connected to the Internet with GPRS or UMTS and it is assumed that the position of the device is known, i.e. that is provided by a positioning service or a GPS receiver. The position is available in the form of coordinates. Furthermore, the existence of a rich database holding POIs and their attributes is presumed. To invoke the geovisualisation service and realise a basic set of functions, it is assumed that the PDA has a Personal Java com-pliant VM and is capable of running applets. The encoding of the visualisation format is done with SVG. Thus the client is presumed to be able to render SVG content.

At Fraunhofer Computer Graphics Center (IGD) a Graphics Engine for Mobile Devices (GEMoDe) based on SVG has been developed. In addition to SVG features this engine allows situative display adaptation (egocentric maps, adjusting font- and display sizes) and can easily be integrated into different mobile platforms by providing only the required components.


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A good overview of the core technologies and some rough guidelines for the development of location based applications that can be applied to the design of geovisualisation services is given in (Hjelm 2002). Frameworks for geoservices based on Open Source software have recently been developed, e.g. (Badard and Braun 2003). Furthermore, many proposals for the architecture of map services specifically based on SVG can be found in the SVG com-munity, e.g. (Schaer 2003; Spanaki and Lysandros 2003; Takagi and Kobayashi 2003). 6.2.1 Platform

The general platform used for the implementation of the proto-typical geovisualisation service is shown in Fig. 56. The core technology is XML. The implementation is based on the Model – View – Control paradigm.

Fig. 56: Implementation platform architecture

Client Hardware and Software

The implemented solutions have been tested on a Compaq Ipaq 3970 PocketPC running under the PocketPC2002 operating system. To display the SVG encoded maps on the PocketPC the TinyLine Viewer, a Java based renderer for the SVG Tiny profile, is used. The Java applet responsible for requesting and displaying SVG content is running on the Jeode VM. Apart from platform-neutral software the Bitflash Mobile SVGB Player 2.0 beta supporting the SVG Basic profile has been used. This version also includes an ActiveX Control for the PocketIE. In HTML embedded SVG documents can be displayed directly in the browser window. For simulating a wireless connection to the server, a Compact Flash 802.11b Wireless LAN card (Wireless Networker™) from Symbol Technologies Inc. was utilized.

(Hjelm , 2002) Hjelm, J. (2002): Creating Location Services for the Wireless Web, New York (NY): John Wiley & Sons

(Badard and Braun, 2003) Badard, T. and Braun, A. (2003): Oxy-gene: An Open Framework For the Deployment of Geographic Web Ser-vices, Proc. ICC 2003, Durban, South Africa, August 10-16, 2003

(Schaer, 2003) Schaer, P. (2003): Database Driven Generation of SVG-Maps with the Apache Cocoon 2 Framework, Proc. SVG Open 2003, Vancouver, Canada. http://www.svgopen.org/2003/papers/DatabaseDrivenSVGMapswithApacheCocoon/

(Spanaki and Lysandros, 2003) Spanaki, M. and Lysandros, T. (2003): A Holistic Approach of Map Composition Utilizing XML, Proc. SVG Open 2003, Vancouver, Canada. http://www.svgopen.org/2003/papers/MapCompositionUtilizingXML/

(Takagi and Kobayashi, 2003) Takagi, S. and Kobayashi, A. (2003): Activities for realization of interoperability of location based services using SVG, Proc. SVG Open 2003, Vancouver, Canada. http://www.svgopen.org/2003/papers/ InteroperabilityofLBS/

TinyLine: www.tyniline.com Jeode VM: www.esmertec.com Bitflash: www.bitflash.com Symbol Technologies Inc.: www.symbol.com


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Server Hardware and Software

Server-side a Windows 2000 Server machine hosts an Apache Tomact (version 4.1.24) application server providing the servlet engine. The adaptive component of the prototype is realised server-side by dynamic generation of SVG with a Java web service (based on Apache SOAP 2.3.1) and Batik 1.5. Batik is an Apache open source Java API for generating and manipulating SVG documents. The SVG maps are adapted to context based on infor-mation sent with the client request and transferred back to the Client. The data sources are accessed with the Deegree WFS 1.1.0. Apart from Batik XSLT transformations are used to transform GML data to SVG. For the wireless client server communication a Wireless LAN access point DWL 900AP+ from D-Link Inc. was installed. 6.2.2 Testbed

Different data sources were used in developing the service and producing the sample maps shown in section 5.4. Table 14 summa-rises the data sources and their characteristics. For the geometric base map surveying data from the Surveying Office of Munich was available as DXF-Files. These DXF-Files were imported in Arcview and converted to native Shapefiles. Minor adjustments to the data were necessary. The base data from the Bavarian State Surveying Office (BLVA) were available as EDBS data. These were converted to Shapefiles before they were loaded in Arcview. All the Shapefiles were exported to SVG documents using the SVGMapper 1.3. These exported base data comprise the feature classes buildings, roads, and rivers. These features build the core layer of information or the base map. Image data for the test data was available as an orthophoto. It was mainly used as a visual backdrop during editing tasks. In addition car navigation data from the company Navtech was available for the whole city of Munich. Some tests with geocoding made use of this data, but no further use has been made for the generation of the mobile map examples. The public transport network in the test area has been digitised in Arcview. Together with the POIs these two data sets build the thematic layer.

Apache Tomcat: jakarta.apache.org Apache Batik: xml.apache.org/batik Deegree WFS: www.latlon.de D-Link: www.dlink.com

SVGMapper: www.svgmapper.com


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Layer Format Scale Geometric base data Digitale Stadtgrundkarte (Vermessungsamt München)

Vector 1:5000

ATKIS Basis DLM 25 (BLVA) Vector 1:25000 Image data Digital Orthophoto (BLVA) Raster Thematic data Car Navigation Database (Navtech)

Vector

Public transport (MVV) Vector Points of interest (POI) Vector

Table 14: Geospatial data sources

For the test area 1418 POIs with attributes were captured and stored as a Point Theme in Arcview (Table 15). These points repre-sent the service layer. The x and y coordinates along with the point ID were exported from the point theme utilising the Arcview script shp2gen into an ASCII file. These x and y coordinates were there-after stored in the attribute table of the point theme, i.e. in the dBaseIV file. Additionally a few sample events were captured (see Table 9).

id name category street hnr x y prior

0 Park Cafe- Next door 15000 Klenzestr. 19 4468366.20 5332529.61 4

1 Comic Company 32004

Fraun-hoferstr. 21 4468387.0 5332503.61 0

2 Lederwaren 32012 Fraun-hoferstr. 23 4468392.46 5332495.15 0

3 Plus Ultra 32012 Fraun-hoferstr. 23 4468401.56 5332485.14 0

4

Bei Vassilis/ Griech. Restaurant 11005

Fraun-hoferstr. 27a 4468427.03 5332458.40 0

5 Tauchsport Manta 50002

Fraun-hoferstr. 23 4468388.76 5332500.59 0

6 Werner's Fahr-schule 62002

Fraun-hoferstr. 29 4468434.00 5332449.95 0

7 Gerlindes Frisurenstueberl 74005

Fraun-hoferstr. 29 4468441.18 5332442.76 0

8 Kunstgiesserei/ Andr. Mayer 73002

Fraun-hoferstr. 31 4468468.80 5332444.79 0

9 Textil-Reinigung 72001 Fraun-hoferstr. 35 4468474.12 5332404.48 0

10 Der kleine Chinese 11011

Fraun-hoferstr. 35 4468480.46 5332397.47 0

Table 15: POI table

Web Feature Server

For the testbed two different data repositories have been config-ured. Firstly, the dBaseIV table containing the POI data (Table 15) acts as a simple data source that can be accessed from a Java appli-cation over a JDBC:ODBC bridge. Secondly, in the Tomcat server the Deegree WFS, a freeware implementation of the OGC WFS


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specification, was deployed. The point database (dBaseIV file) was therefore converted to a MS Access table. This table was registered as a data source in the WFS Capabilities description file: ... <FeatureTypeList> <FeatureType> <ResponsibleClass className="org.deegree_impl.services.wfs.db.PointDBDataStore" configURL="file:///C:/deegreewfs/webspace/WEB-INF/xml/poi_config.xml"/> <Name>poi</Name> <Title>main POI around TUM</Title> <SRS>EPSG:4326</SRS> <LatLonBoundingBox minx="-8" miny="15" maxx="240" maxy="290"/> </FeatureType> ... </FeatureTypeList> </WFS_Capabilities>

6.2.3 Prototype functionality

The prototype geovisualisation service has only very basic func-tionality. The client acts as a geographic information viewer and the server provides the handling of client requests and basically generates the SVG maps. The overall architecture is depicted in Fig. 56. Functionality of Client

The client tier is constituted by an applet running on the mobile device. As a map viewer the TinyLine viewer is used. Although TinyLine only supports the Mobile SVG Tiny Profile, this use case demonstrates the core functionality of the geovisualisation service and shows basic visualisation possibilities of SVG on mobile devices. The main map functions provided by the viewer are the display of SVG maps and the panning and zooming within the displayed map. Fig. 57 (left) shows a screenshot TinyLine viewer and its available map functions: select, pan, zoom in, zoom out, and reload.

To show some more advanced features (e.g. opacity, filters, trans-formations of text (rotate) etc.) supported by Mobile SVG Basic Profile, the Bitflash ActiveX Plugin for the PocketIE is used. With the Bitflash viewer SVG documents embedded in HTML are directly displayed in the PocketIE browser window.

TinyLine: www.tyniline.com


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Fig. 57: TinyLine viewer applet and mock-up client

The applet should at least provide a very basic interface for initi-ating user requests. Fig. 57 (right) depicts a mock-up of such an interface. The button panel on the bottom is only visible if needed and through a click on one of the icons, a specific mobile spatial action is selected. Depending on the action chosen the user inter-face would extrude further widgets according to the use cases shown in Table 13. With the chosen actions and its associated parameters the user goal is at least roughly defined. Functionality on Server

The server side functionality is more ample and complex. A Java web service implemented as a SOAP service accepts SOAP requests from the client as input and invokes the adaptation methods. The responsibility of the service is to extract the SOAP message and analyse the contained context. Then decisions about adaptation necessity and appropriate methods have to be taken. A next step includes the design of filters and the generation of a WFS request or an SQL string for a direct database connection that looks like sketched below: <?xml version="1.0" encoding="iso-8859-1"?> <wfs:GetFeature outputFormat="GML2" xmlns:gml="http://www.opengis.net/gml" xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc"> <wfs:Query typeName="poi"> <ogc:Filter> <ogc:PropertyIsEqualTo> <ogc:PropertyName>/poi/code</ogc:PropertyName> <ogc:Literal>11001.0</ogc:Literal> </ogc:PropertyIsEqualTo> </ogc:Filter> </wfs:Query>

</wfs:GetFeature>

The service then accesses the WFS or the POI database and retrieves the features. In the case of the WFS the features are returned as GML and are transformed to SVG with XSLT. If a

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database table with point data is directly accessed the data can be processed form the service with Batik to generate SVG elements. The following code snippet shows parts of an XSL stylesheet: <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" ... <xsl:template match="/"> <svg width="799.167" height="936.903" viewBox="4468150 -5333450 1000 1333"> <defs>  <symbol id="56006.0"> <rect x="10" width="50" y="10" height="50" style="fill:rgb(90,90,255);stroke:rgb(64,64,255);stroke-width:7"/> <text x="15px" y="52px" style="fill:rgb(64,64,255);font-size:48;font-family:Arial"> M </text> </symbol> </defs> <g id="dynamic"> <xsl:apply-templates select="//poi.Code"/> </g> </svg> </xsl:template> <xsl:template match="//poi.Code"> <xsl:element name="use"> <xsl:attribute name="x"><xsl:value-of select="substring-before(..//gml:coordinates,',')"/></xsl:attribute> <xsl:attribute name="y"><xsl:value-of select="-substring-after(..//gml:coordinates,',')"/></xsl:attribute> <xsl:attribute name="xlink:href">#<xsl:value-of select="."/></xsl:attribute> </xsl:element> </xsl:template> </xsl:stylesheet>

In both cases a transformation has to be applied to the coor-dinates, because SVG has an image oriented coordinate system (Fig. 58). In order to be displayed correctly, the y-coordinate from the GML document or the database table has to be set negative. The test data are encoded in the German Gauss-Krüger spatial ref-erence system with a positive y-coordinate. Therefore a flip transformation has to be applied. In addition, a transformation to an ‘image’ coordinate system, the normal SVG coordinate system, can be applied.


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Fig. 58: Coordinate systems of GML and SVG

The service can have several methods to adapt the map that is sent back to the client. The two basic groups of methods are:

• map symbology adaptors: these methods can have global or more local effects. Changing the symbology for the complete map can be done with an exchange of the style sheets (CSS or XSLT). For partial changes the elements can be manipulated through the DOM (e.g. assigning a different opacity value).

• map components configuration adaptors: these methods can either configure the individual components of base map and/or configure additional landmark and thematic components (e.g. transport network).

Fig. 59 illustrates the communication sequence of the geovisuali-sation service between the client and the server.

Fig. 59: Sequence diagram of the geovisualisation test service


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Adapmap engine

The proposed design of the ‘adapmap’ map adaptation engine is illustrated in the following UML diagram (Fig. 60).

Fig. 60: Adapmap architecture

This high-level architecture of the adapmap engine aims at showing the basic components and the utilisation of several open source APIs. The WFS service is based on the Deegree WFS. Batik is used for generating and manipulating SVG. The transformer service relies on XSLT. To compute spatial relationships Java Topology Suite might be used. Among other additional services the match-ing service can be used for integrating other data sources.

The adapmap engine uses different XML technologies to manipu-late the map features encoded as SVG. For the adaptation of SVG encoded maps the DOM is specifically important. The DOM is a language and platform independent representation of an XML document in the memory and can thus be accessed during run time of an application. Fig. 61 shows besides the DOM the other important mechanism for XML processing: the Simple API for XML (SAX). SAX can be used to parse an XML document. This process is event-based, i.e. if the parser gets an event (an element), it notifies the application which will take some action.


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Fig. 61: SAX and DOM cooperation (McLaughlin 2001)

SOAP

For the communication between client and server the SOAP proto-col is used. SOAP is a platform neutral, XML based message protocol for web services specified by the W3C. SOAP has no lan-guage and transport protocol binding, though in most cases it is used over HTTP. A SOAP service is based on exchanging mes-sages. Such a SOAP message is an XML document with the following structure (Cerami 2002):

• an Envelope element, the root element containing all other elements

• an optional Header element specifying header informa-tion such as authentication

• a Body element giving details about call and response information

• an optional Fault element providing information about errors that occurred while processing the message

The following code example shows the SOAP request of the client with the basic context parameters: <?xml version="1.0" encoding="UTF-8"?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <SOAP-ENV:Body> <ns1:retResponse xmlns:ns1="urn:examples:testservice" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"> <loc_x xsi:type="xsd:int">4468540</loc_x> <loc_y xsi:type="xsd:int">-5332680</loc_y> <cal xsi:type="xsd:date">2003-11-18</cal> <screen_x xsi:type="xsd:int">240</screen_x> <screen_y xsi:type="xsd:int">320</screen_y> <usergrp xsi:type="xsd:string">C</usergrp> <cat xsi:type="xsd:string">11001.0</cat> </ns1:retResponse> </SOAP-ENV:Body> </SOAP-ENV:Envelope>

(McLaughlin, 2001) McLaughlin, B. (2001): Java and XML, Sebastopol (CA): O'Reilly & Associates

(Cerami, 2002) Cerami, E. (2002): Web Services Essen-tials, Sebastopol (CA): O'Reilly & Associates


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SOAP can be used to encode the context and parameters and the user request in an interoperable standard protocol.

Several improvements and refinements of the implementation are imaginable regarding extent of adaptivity, client functionality and user interface, and adjustments to other implementation approaches.

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Chapter 7

7 Conclusion

Inanimate objects are classified scientifically into three categories - those that donʹt work, those that break down, and those that get lost. – Russell Baker.

7.1 Achievements

The basic hypothesis of this research is that introducing adapta-tion mechanisms into geovisualisation services can significantly improve the usability of geographic information on mobile devices. The adaptation concept is embedded in a coherent conceptual framework of visualisation for mobile users. The assessment of existing approaches and solutions (sec. 3.3) has justified the applied top-down methodology of combining existing theories and approaches to the mobile cartography framework. The strength of widening the scope of awareness services from location-aware to context-aware has been demonstrated in chapter 4.

As stated in chapter 1, the primary goal of this research has been the elaboration of a new research field in cartography by extending cartographic theories to the application domain of mobile com-puting. For the understanding of map usage several useful theories have been studied in cartography. A review of these theories in chapter 2 reveals that activity theory, human-computer interaction, and cognitive theory have been applied to map usage inde-pendently from one another and without taking the mobile context into account. Context theory was reduced to a matter of location. The proposed conceptual framework presented in chapter 4 com-bines these theories to improve the usability of mobile geographic information usage.

The conceptual framework contributes to enriching and extend-ing the cartographic theory and methods in the field of geographic information communication in mobile environments and

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incorporating adaptation methods into geovisualisation. Specifically, this research has achieved the following:

• introduction of new concepts for mobile cartography and a differential definition of mobile cartography opposed to traditional cartography and web cartography

• extension of cartographic theory through the transfer of adaptation concepts and the proof of its value to the domain of cartography in general and mobile cartography in particular

• enrichment of cartographic theory by introducing a ser-vice oriented concept

• design of adaptation methods that enhance the carto-graphic methodology and enable the discipline to cope with numerous challenges posed by new technological and societal advancements

• proposal of first design studies of adapted geovisualisa-tion for mobile cartography for subsequent research and usability tests

• proof of applicability of adaptivity within a mobile geo-visualisation service through a prototypical implementa-tion

The main accomplishment of this research is the demonstration of how beneficial the development of a systematic framework is for mobile map usage. The examples of adapted maps that were par-tially generated with the geovisualisation service described in chapter 6 express how adapted geovisualisation can contribute to improve the usability of mobile geovisualisation and geographic information usage. The results confirm the proposed methodology and are reasonably congruent with other studies (Edwardes et al. 2003b; Heidmann and Hermann 2003; Zipf 2002; von Hunolstein and Zipf 2003).

7.2 Insights The value of the framework has been demonstrated by subjecting the basic user actions to the adaptation methods developed before within the context of the sample scenarios. The combination of different context dimensions has several advantages over a more one-sided approach as for instance LBS. The sole use of location as context parameter does not always lead to value-added solutions. The more comprehensive approach that includes time, personality, user activity, co-located information, etc. has a better chance to enhance the overall relevance of the service and thus the user

(Edwardes et al., 2003b) Edwardes, A., Burghardt, D. and Weibel, R. (2003b): WebPark - Location Based Services for Species Search in Recreation Area, Proc. 21st Internat. Cartographic Conference, Durban, South Africa, August 10-16, 2003

(Heidmann and Hermann, 2003) Heidmann, F. and Hermann, F. (2003): Visualisierung raumbezogener Informa-tionen für ultraportable mobile Systeme, in, Visualisierung und Erschließung von Geodaten - Seminar GEOVIS 2003, Kartographische Schriften, Band 7, Bonn: Kirschbaum Verlag, 121-131

(Zipf, 2002) Zipf, A. (2002): User-Adaptive Maps for Location-Based Services (LBS) for Tour-ism, in K. Woeber, A. Frew and M. Hitz (Eds.), Proc. of the 9th Internat. Conference for Information and Communication Technologies in Tourism, ENTER 2002, Innsbruck, Austria, Springer Computer Science, Berlin; Heidelberg: Springer-Verlag. http://www.eml.villa-bosch.de/english/ homes/zipf/ENTER2002.pdf

(von Hunolstein and Zipf, 2003) von Hunolstein, S. and Zipf, A. (2003): Towards Task Oriented Map-based Mobile Guides, Proc. Internat. Workshop "HCI in Mobile Guides" at Mobile HCI 2003, 5th Internat. Symposium on Human Computer Interaction with mobile Devices and Services, Udine, Italy, September 8-11, 2003

7 Conclusion

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satisfaction. The use of more context parameters also facilitates the interoperability with other services which once more can enforce the effect of a relevance improvement. The consultation of a multi-dimensional context allows to generate egocentric geovisualisation beyond the spatial notion of ego-centre.

This work has concentrated on bringing together the relevant building blocks. Yet, a precondition for a successful implementa-tion of more comprehensive, adaptive mobile geovisualisation services is the formalisation of context, cartographic knowledge, as well as rules and constraints governing them. First attempts to formalise relevant context parameters have been proposed, a refinement of the formal models gives rise to hopes for improved results.

The map examples have revealed that generalisation alone guar-antees legible maps, but not necessarily egocentric and relevant maps. Generalisation is absolutely indispensable for small display geovisualisation in mobile cartography. However, it is a prerequi-site on mobile devices, but not sufficient to improve the usability. Especially in mobile usage situations an adaptation of the geovisu-alisation is needed.

It should be noted that this research has examined only the adaptation of presentation objects. Yet, the adaptation of the user interface to the mobile usage context is of equal importance. The style and modes of interactions, the functionality offering have to be reconsidered. Most promising are multimodal interfaces that use more than one input and output channel. Such multimodal interfaces provide a greater potential of adaptation in mobile usage situations.

One basic assumption for the service design was the availability of a rich geospatial data pool. In reality it is much more compli-cated. Several data sources with different geographic coverages, scales, feature classes, projections etc. could be available for an area of interest causing manifold interoperability challenges. Service roaming constitutes another problem. Apart from roaming in mobile networks, a geovisualisation service should provide geographic and thematic roaming. This means a service should possibly offer the same data in the whole area of its coverage. The problems of syntactic and semantic interoperability caused by such geo data ‘roaming’ require data integration (matching and confla-tion) and harmonisation mechanisms that are examined in the GiMoDig project.

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It has been found difficult to capture the user requirements for an adaptive geovisualisation service. The thesis presented scenarios as a method of analysing user requirements for supporting services in a mobile, everyday life. These oversimplified examples certainly need systematic improvements for being useful in designing a concrete service. Strongly connected to that point is the catalogue of basic user actions in mobile cartography. It has proven its use-fulness for the purpose of reducing the complexity and designing first adaptation methods. Further developments might reveal a different, adjusted categorisation. In this context the establishment of activity ontologies will become a prime issue in the future.

The thesis has addressed only questions of the adaptation poten-tial for mobile cartography. For any kind of context-aware service privacy issues are a major factor. The handling of these issues will be the gauge for success or failure of such services. Collaboration with specialists from other fields is therefore vital.

7.3 Outlook 7.3.1 Suggested improvements

The framework developed in chapter 4 and the application of the adaptation concept in chapter 5 have introduced a broader view of cartography for mobile users. Nevertheless, both the framework and the adaptation are still far from being exhaustive and can be refined in many dimensions.

For the work in general extensions have to be made regarding the test set. More and different test areas (urban, rural, dense, wide, alpine, tourist areas, etc.), additional scenarios and concrete use cases may bring to light further requirements, problems, and diffi-culties. Experiences from other projects (Krug et al. 2003; Nivala et al. 2003), could help in new test designs.

So far the results have only been judged subjectively by the author. Although the utility and usability of adapted maps seem to be present, the hypothesis can hardly be confirmed with confi-dence unless the subjective judgement is integrated with well defined objective criteria. Empirical usability studies, for instance, have proved feasible for the evaluation of the proposed solutions and can be conducted in the manner presented by (Nivala et al. 2003; Heidmann and Hermann 2003).

For the geovisualisation, incorporating recent approaches from the generalisation community (e.g. MRDB, radial generalisation, etc.) and solutions for the automatic generation of topograms or schematic maps are crucial to achieve appropriate graphic results.

(Krug et al., 2003) Krug, K., Mountain, D. and Phan, D. (2003): WebPark: Location-Based Services for mobile users in protected areas, Geoinformatics(March). http://www.soi.city.ac. uk/~dmm/ research/pubs/WParticle_by_Consortium_ GeoInformatics_nr2_March_2003.pdf

(Nivala et al., 2003) Nivala, A.-M., Sarjakoski, L. T., Jakobsson, A. and Kaasinen, E. (2003): Usability Evaluation of Topographic Maps in Mobile Devices, Proceedings 21st International Cartographic Confer-ence, Durban, South Africa, August 10-16, 2003

(Heidmann and Hermann, 2003) Heidmann, F. and Hermann, F. (2003): Visualisierung raumbezogener Informa-tionen für ultraportable mobile Systeme, in, Visualisierung und Erschließung von Geodaten - Seminar GEOVIS 2003, Kartographische Schriften, Band 7, Bonn: Kirschbaum Verlag, 121-131

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A closer integration of the presented service architecture within a general platform as proposed by (Edwardes et al. 2003a) is able to reduce the development efforts and use synergetic effects.

The integration and modelling of constraints in adaptive maps is important to solve graphical conflicts arising from dynamic map generation in a mobile geovisualisation service. Approaches of embedding constraints in SVG and constraint-based generalisation need to be evaluated for their usefulness.

A major challenge of any adaptivity approach is the anticipation of user information needs. In mobile cartography this particularly concerns the inference mechanisms for mobile user activities (spa-tial behaviour). Thus research on ontologies of ‘mobile user activities’ has to be continued. Again, empirical research has to find mappings from typical activities to most commonly used information types and presentations.

Similarly context modelling has to be refined. Especially the modelling of the inter-relationships of different context domains requires extended investigations. Methods of extracting rules valid for specific context types are essential and could be found in other disciplines.

With regard to adaptation the domain could be enlarged from mobile cartography to cartography and geoinformatics in general. In cartography many more applications can be envisaged that would profit from adaptation. For this sake the adaptation approach described in this dissertation needs to be refined and extended along with the development of their evaluation methods. An important extension of the adaptation approach is the adapting of geo user interfaces. The rich research work from adaptive user interfaces could be combined with approaches considering users acting with cartographic and/or geographic information systems. Questions are how the user interface might be adapted according to mobile user actions, different user groups, user roles, etc.

Future work can be done in many fields. The service implemen-tation requires many enhancements. First of all further adaptation methods have to be implemented. Additionally interfaces to dif-ferent context sensors (e.g. GPS) must be incorporated. The design should be adjusted to be compatible with common generalisation architecture and can be extended with other modules (e.g. gener-alisation, conflation, feature matching). Furthermore stricter conformance to OGC services should be attempted.

An interesting addition to the geovisualisation service concept is the development of adaptor tools. The idea behind adaptor tools

(Edwardes et al., 2003a) Edwardes, A., Burghardt, D., Bobzien, M., Harrie, L., Reichenbacher, T., Sester, M. and Weibel, R. (2003a): Map Gen-eralisation Technology: Addressing the Need for a Common Research Platform, Proceedings 21st International Carto-graphic Conference, Durban, South Africa, August 10-16, 2003

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is that the user can configure his/her own ‘adaptors’ for known contexts on a desktop computer and take these adaptors with him on the mobile device. These adaptors can include e.g. profile, pref-erences, filters, style, etc.

Finally, it should be evaluated how new technologies like Aug-mented Reality (AR) relate to mobile cartography and how they can meaningfully be combined with this approach. 7.3.2 Concluding remarks

The euphoria of 3G telecommunication and LBS in its entourage has receded. The promise of an ‘anything, anytime, anywhere’ world does not seem to come true in the near future. Nevertheless, the trend to more individualised, mobile used services is irreversible. The future-oriented research that deals with questions of adapta-tion, privacy concerns, representations, etc. already bears fruits in today’s cartography. The methodological progresses and the insights gained have opened new perspectives for the follow-up work.

155

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Appendix: Abbreviations • A-GPS: Assisted Global Positioning System • AT: Activity Theory • DOM: Document Object Model • GML: Geography Markup Language • GPRS: General Package Radio System • GPS: Global Positioning System • HCI: Human Computer Interaction • HSCSD:High Speed Circuit Switched Data • LBS: Location Based Service • OGC: Open GIS Consortium • PDA: Personal Digital Assistant • POI: Points of Interest • SMIL: Synchronized Multimedia Integration Language • SOAP: Simple Object Access Protocol • SVG: Scalable Vector Graphics • UDDI: Universal Description, Discovery, and Integration • UM: User Model • UMTS: Universal Mobile Telecommunications System • WLAN:Wireless LAN • WFS: Web Feature Server • WMS: Web Map Server • WSDL: Web Service Description Language • XML: Extensible Markup Language • XSL: Extensible Stylesheet Language • XSLT: Extensible Stylesheet Language Transformation

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